Fishes For The Aquarium

Names

As with the plants, so among fishes there are many which have no English name, though as they become popular they tend to acquire them. Generally speaking, however, it is better to learn the scientific names, because these are internationally used, and more exact. These names are usually derived from Greek or Latin words, often descriptive of some feature of the fish or plant concerned. They are always in two parts. The first part, beginning with a capital letter, is called the generic name, and indicates the group to which the species belongs; the second part, always beginning with a small letter, is the trivial name, indicating the particular species. Thus we may have the names Barbus ticto, Barbus tetrazona, and Barbus titteya; the fact that the first part of the name is the same in each case shows that these fishes are related to one another, belonging to the genus Barbus. But they are different species, and so each has its own special part of the name, the second part. It is much the same principle as surnames and personal names. Such a name as tetrazona, which means four-banded, may be found in some other genus, just as there may be plenty of Johns and Charlies with different surnames; but the combination of the two names Barbus tetrazona is unique, and can apply only to this one species of fish. By this method scientists arrange that each plant or animal has a double-barrelled name by which it is distinguished from all others and recognizable by scientists of all countries. It will be seen that this system has an advantage over names applied in the local language, which are not only unfamiliar to people of other countries, but often vary from one town to the next.

On the other hand, scientific names reflect our knowledge of the creatures concerned, and sometimes they have to be adjusted as the result of some new piece of research. It might be found that what we called Barbus ticto, supposed to be found in India and Burma, was actually two species, one in India and one in Burma, in which case one of them would need a new trivial name to distinguish it; or what we regarded as two species may prove to be only one, in which case one of the names would cease to be used—it would be a synonym of the other. Such matters are the concern of scientists, but the aquarist is sometimes puzzled, and occasionally indignant at these "changes", more properly corrections, of names, so I mention them here.

It will be noticed that the scientific name is printed in italics. This is the accepted practice, and distinguishes it at once from the common or popular name.

Classification

More than twenty thousand kinds of fishes have been discovered, of which about a third come from fresh waters; new ones are being found every year.

This vast assemblage is classified by scientists according to their relationships as shown by careful study of their structure and way of life. The genera, or groups of related species, are put together in families (groups of related genera), and these into orders.

For our present purpose it is not necessary to go into all this, but merely to remark that broadly speaking the more primitive kinds of fishes have only one dorsal fin, mostly with soft rays, and often an adipose fin, while the pelvic fins have no spines; the more advanced fishes (those which evolved more recently) have the dorsal fin in two parts, the front part bearing spines, and have always a spine in front of each pelvic fin, and usually two or more in front of the anal fin.

Only a mere handful of the known species—about 200— are familiar to the aquarist, and for him there is a much more useful classification. Firstly, fishes can be divided into tropical and cold-water species.

The tropical fishes can be divided again mostly according to the way they breed. First, there are the livebearers, which give birth to young ones much as higher animals do; secondly there are those that lay eggs and take no further interest in them—perhaps even eating them as soon as they are laid; thirdly, we have those which lay eggs but take care of them, and these can be again divided into those that make a nest of bubbles at the surface, and those that protect them in other ways. That is the arrangement which will be used in the pages which follow. It is not quite so different from the scientific classification as might be supposed, because as a general rule the more primitive kinds of fishes leave their eggs to their fate, while the more advanced kinds, with spinous dorsal fins, more often have ways of caring for their young.

Tropical fishes are considered first because, as already stated, they are easier to keep and recommended for the beginner. Some of the other species are not for beginners, but as I hope this book will'be your guide when you are more experienced, I have thought it useful to include them.

A. Tropical Fishes
The Livebearers (see Plate 1)

It is fitting that these fishes should take first place on our list, because they are the best of aquarium fishes—colorful, lively, easily tamed, not fussy about water or food, and breeding freely.

The name Livebearers refers to the fact that the eggs hatch out within the body of the female, and the young fish are not liberated into the water until they are well-developed enough to swim about and feed.

This means that the eggs must be fertilized internally, and for this purpose the male fish is provided with a special structure known as a gonopodium, formed by the front part of the anal fin. The sexes are therefore easy to distinguish in these fishes, and the veriest novice can be sure of getting a pair. The female is often larger than the male. Another remarkable thing about them is that a single fertilization enables the female to produce two or three, or even more, broods of young, so that it is possible to purchase just one healthy, plump female and soon have a thriving family. Most females, in fact, will be found to be in this condition, and can easily be recognized by a dark patch showing through the flesh at the end of the body cavity, known as the "gravid spot".

The broods are produced usually at six- to eight-week intervals, and average about 25 young. These grow quickly and become mature after two or three months, but they are still small at this time, and if allowed to breed will not grow much larger.

From this you will see that it is economical to begin with Livebearers, for a pair will soon populate the tank. Even then you must not expect to be able to keep all the young which are produced; the parents will eat some, unless you have another tank to move them into, a few weaklings will die off, and of those that remain only as many as the tank will support when they are fully grown should be kept. In a "community tank"—where a number of other kinds of fishes are kept— very few, if any, of the young will survive, but they make valuable food for the others. For those who wish to breed these fishes seriously, further information is given in another chapter.

Most of the Livebearers belong to one family of Central and South American fishes called Poecilidae. Those most interesting to the aquarist are as follows:

Heterandria formosa(Mosquito-fish). The popular name seems to have arisen from the small size; the male is only about three-quarters of an inch long, and the female an inch. The color is olive-green above and white below, with a dark band along the side, and sometimes black vertical stripes. Being so small, they need the finer grades of dried food, or very small live foods such as micro-worms or the smallest sifted daphnia. The birth of a brood extends over a week or more, two or three young being dropped every day. If parents are well-fed and floating plants are given as cover, the young will not be eaten; they need very small foods; powdered yolk of egg is suitable. The smallest of the Livebearers, it should not be put with other fishes (Fig. 7, A and B).
Lebistes reticulatus (Guppy). Most famous of the Livebearers, and one of the most variable. Males rarely more than one-inch long, with bright colors seldom the same in any two individuals; females two inches or more in length, usually plain olive-colored, but variegated strains have been bred. Special societies have been formed for the study and development of this species, and careful breeding has produced some beautiful varieties, in which the male caudal fin is enlarged to form long streamers and decorative shapes; some color-varieties, such as a plain golden one, have also been established. Such breeds are still rather expensive, and not easy to get, however, and the beginner should be content with ordinary ones, whose variability is fascinating enough.

The Guppy is a very adaptable fish, and can be kept in a smaller tank than most others, and tolerates a temperature range of from 6o° to 95°F.; but it is particularly sensitive to a sudden temperature drop and may succumb to this more quickly than other kinds. Takes medium dried food and almost any other fish-food if not too large. Breeds best at nine months to a year, and is old at two years.

Mollienisia latipinna (Broad-finned Mollie). A Livebearer which needs the largest tank that can be provided. It grows to three and a half inches in length, the sexes being much the same size. The dorsal fin is large, especially in the male; it begins farther forward than the pelvic fins in both sexes. Most wild specimens are gray with brilliant metallic reflections, and rows of dark spots on the dorsal and caudal fins. But a splendid black variety has been developed; this begins life as a gray fish, but soon black spots and patches appear irregularly on the body, which gradually spread until the whole is rich velvety black; sometimes there is a bright orange border to the caudal fin by way of contrast.

Most black Mollies nowadays, however, are what are called Permablack; these are black from birth, and are said to have been first obtained by crossing this species with the next; they do not grow very large, however, and are not easy to breed. The female often looks full of young, but later reabsorbs them. It is better to get the real species if possible, and wait for the black to develop.

Mollies are largely vegetarian, and like the moss-like algae which grows on glass rocks and plants in a tank with plenty of light; they are useful in cleaning a tank overgrown with this. Otherwise they must have a preparation of finely chopped spinach or lettuce in their diet. A little sea-salt in the water is beneficial to them.

Mollienisia sphenops (Short-finned Mollie). Like the preceding, but the dorsal fin is much smaller, beginning farther back than the pelvic fins; color as above, but there is a charming variety with bluish body, and fins banded with black, yellow and red, called the Liberty Mollie.

Mollienisia velifera (Sail-finned Mollie). The largest and most spectacular of the Mollies, with a deeper body and the dorsal fin even farther forward and higher than in M. latipinna. Not often available.
 

FIG. 7

A) Heterandria formosa, male; B) same female; c) Dermogenys pusilla

Xiphophorus helleri (Swordtail). One of the best of all fishes for the beginner. It grows to three inches or more in length, the sexes being about the same size, but the male is distinguished, when mature, by a long, sword-shaped extension of the lower part of the caudal fin; in a good fish this should be straight, and the longer the better; the dorsal fin should also be longer than high. Unfortunately, it has been crossed so much with the species which follows that these characters are usually poorly developed. It is not uncommon for a female to develop male characters, even after bearing young.

There are several color-varieties. The original wild form, still one of the prettiest, is green, with a red zig-zag stripe along the side, the "sword" being yellow with black edges. Red and black (plain or mixed), golden and albino varieties are known, some of them obtained by the crossing mentioned.

Swordtails are easier to keep and breed than Mollies, being less particular about food and water; they do better in hard, or slightly salt water, however, and like plenty of light. They live for three years or more. Sometimes a large male will bully smaller fishes. They are liable to jump out of the water, so an aquarium cover is essential.
Xiphophorus maculatus (Platy). Very similar to the preceding, but should have a shorter, deeper body, no "sword" in the male, and the dorsal fin should be short and fan-like. Red, blue, black, golden and particolored varieties are known; often there is a black blotch or pair of spots at the base of the caudal fin. A handsome new variety is called the "Wagtail", having a red or golden body with black fins.

When crossed with the Swordtail it produces fertile hybrids, and pure specimens are consequently scarce nowadays. If, therefore, you are able to get specimens conforming to the specifications given here, do not keep Swordtails and Platys together, for this will very likely spoil both.

Xiphophorus variatus (Variable Platy). This is distinguishable from the ordinary Platy by the dorsal fin, which has a longer base, and a very convexly rounded margin; this fin is usually yellow with a black border in the males. The body color is generally yellow with a certain amount of green reflections, and may have either black spots or vertical stripes. In the best specimens the caudal fin is brilliant red. Females are shining olive-green, with some black horizontal stripes and a dark band across the base of the caudal fin. Both sexes reach about two inches long, and live for about three years. The colors of the male do not appear until he is about four months old.

A number of other species of Livebearers can be obtained from time to time, but have not the general usefulness of the above. The only other that need be mentioned here is a curious species belonging to a different family:

Dermogenys pusillus (Half-beak). The nearest relations of this little fish are the garfish and flying-fishes, most of which live in the sea, and are not viviparous. The prolonged lower-jaw of this species gives it a very distinctive appearance, but otherwise it is not remarkable; the color is olive above, white below, with some red in the lower fins. It feeds at the surface, on dried or live foods, and is liable to jump, so a cover is necessary. A little sea-salt in the water improves chances of longevity and breeding (Fig. 7, c).

The Egglayers

In the great majority of fishes the eggs are laid by the female before fertilization, which is usually accomplished by the male as he follows her round. Some lay a very large number in order to allow for the very high mortality which follows; such fishes take no further interest in the welfare of their offspring, but in fact very often eat as many as they can; similarly when the young hatch out, very small and helpless, they are liable to be preyed upon by their own parents. For the first day or two they feed by absorbing the remains of the yolk of the egg, which is enclosed in the body cavity, but by the time they have finished this they are able to swim freely and to catch microscopic animals. Most of the fishes which abandon their eggs to their fate in this way belong to the more primitive families already mentioned, without a spiny first dorsal fin. We will now consider them under family headings which have become familiar to aquarists.
The Charagins (pronounced Karrasins) (see Plate 2 and Fig. 8)

These form a large group of freshwater fishes, found only in Central and South America and in Africa. This distribution is found in some other groups (cf. the Gichlids) and is one of the proofs put forward that these continents were once connected. The Characins show great variety, but are always soft-rayed, with very often an adipose fin; they are related to the Carp and Goldfish family, but differ in having teeth in the jaws. They include many of the best aquarium fishes, and unless otherwise stated it may be taken that they will live peacefully with others in the same tank, take ordinary prepared foods, and have average temperature requirements from 650 to 8o°F. Males often have hooks on the tip of the anal fin which stick to the net when they are handled, especially in the commonest groups, Hemigrammus and Hyphessobrycon.

Anoptichthysjordani (Blind Characin). A novelty from certain caves in Mexico. It is the subterranean form of a common species from above-ground streams, Astynax mexicanus, and that should really be its name. The eyes and pigment have been lost through living in the darkness of caves, but it manages quite well in the aquarium and holds its own with other fishes. Grows to about three inches long; takes most foods (Fig. 8, A).

Aphyocharax rubripinnis (Bloodfin). This fish, from Argentina, is not strictly tropical, and therefore can endure rather lower temperatures than most. It is silver, with some blood-red in all the fins, and is rather less than two inches long {see Plate 2).

Copeina arnoldi. A beautiful slender bluish-gray fish, the male reaching three inches in length, female a little smaller; fins yellow with reddish tints, the male with a white spot at base of the long dorsal fin. This is exceptional among Characins in that it protects its eggs, but adopts the surprising process of laying them above the surface of the water; the parents have to leap together in order to accomplish this; the eggs are then kept moist by the male, who splashes them regularly (Fig. 8, c).

Copeina guttata. More stout-bodied than the preceding, the fins rounded instead of pointed. The body is gray-blue above, and the pale yellow dorsal fin has a dark patch; other fins are yellow tinged with red; the male is distinguished by small reddish spots, one on each scale. The eggs are laid in a hollow in the sand, and guarded by the male; this is sometimes done in a "community tank" with other species present, but to ensure success they should be given their own tank. Both species of Copeina are from Brazil.

Corynopoma riisei (Paddle-gill). A silvery fish, growing to about two inches long, the male of which has dorsal and lower part of caudal fins much enlarged. The male is also remarkable for a very long extension of one of the gill bones on each side, at the end of which is a small shining blade of skin. This can be set out at an angle to the body, and at breeding time becomes laden with sperm; the female snaps at it (often damaging it) and so gets sperm in her mouth. So when she takes her eggs in her mouth to fix them to the leaf of a plant, they become fertilized. She then takes care of them till they hatch, and so is another exception to the usual Characin habit. This interesting fish comes from Trinidad and Colombia, and is usually available (Fig. 8, D).

Ctenobrycon spilurus (Knife-fish). A deep-bodied, gleaming silver fish, growing to more than three inches long, with a dusky blotch at the shoulder. The female is usually larger than the male, and distinguished by some red in the anal fin. Comes from Guiana, and is one of the best aquarium fishes (Fig. 8, E).

Gasteropelecus (Carnegiella) strigata (Hatchet-fish). A dainty fish from Brazil with a very deep, sharp-edged body and long pectoral fins. A great jumper, and said to fly over the surface of the water; must have a cover. Needs rather high temperature (8o° to go°F.). Three oblique dark bands, small size (11/2 inches), no adipose fin, and more delicate shape distinguish it from Gasteropelecus stemicla, which is more silvery, with a dark stripe along the side, and usually larger (two inches or more). This and another called G. levis are practically impossible to distinguish from one another in the aquarium. An adipose fin is present. They inhabit Guiana and Brazil. Hatchet-fishes are never common and rather  delicate—not for beginners  (Fig. 8, B)'

Glandulocauda inaequalis. A nicely-shaped gun-metal-blue fish, with the lower lobe of the caudal fin larger than the other and a gland-like scale at the base of it in the male. The upper part of the eye is conspicuously red, and the vertical fins are tipped with white. At intervals it conies to the surface and takes a bubble of air with a little noise. Comes from Brazil, and grows to about two and a half inches (Fig. 8, F)

Gymnocorymbus ternetzi (Widow-fish). Silvery, with the rear half of the body, and particularly the large anal fin, black; two black bands across front part of body. This very effective species, from Paraguay, looks best at about one and a half inches long; after that the black tends to fade; it also gets paler when the fish is cold, sick, or asleep (Fig. 8, G).

FIG. 8

Characins. A) Anoptichthys jordani; B) Carnegiella strigata; a) Copeina arnoldi; D) Corynopoma riisei; E) Ctenobrycon spilurus; P) Olandulocauda inaequalia; G) Gymnocorymbv& ternetzi; H) Hemigrammus caudovittatus; J) Hemigrammus pulcher; K) Hemigrammus unilineatus; L) Hyphessobrycon heterorhabdusi (M Hyphessobrycon pulchripinnis; N) Hyphessobrycon serpae; p) Hyphessobrycon
sholtzei
 
Gymnotus carapo. A fascinating novelty for anyone willing to devote a tank to one fish. It grows to nine inches or more in length, and becomes very tame. The vicious-looking mouth and wicked little eyes belie it, for it is not savage. It is rather long and eel-like, handsomely striped in shades of brown, and moves backwards or forwards with equal ease by simply waving its long anal fin; there is no dorsal or caudal fin. South American, related to the famous Electric Eel; not really a Characin, but included here for convenience. Must have live or fresh food.
Hemigrammus caudovittatus (Buenos Aires Tetra). A handsome fish growing to three inches in length. Comes from Argentina and tolerates lower temperatures than some; also does better in hard water. Body silver, all fins except pectorals reddish; a black cross with halo of yellow at base of caudal fin. Sometimes bullies other species (Fig. 8, H).

Hemigrammus erythrozonus (Glow-light Tetra). A very beautiful fish, an inch or more in length, whose main feature is the shining red eye, like a red-hot coal, an effect which is continued in a streak along the side. There is also a dash of red in the dorsal fin. The rest of the fish is more or less transparent. Found in Guiana (see Plate 2).

Hemigrammus nanus (wrongly called Hasemania marginata). This dainty little fish from Brazil, growing little more than an inch long, is chiefly attractive because of the gleaming white tips to its fins and at base of caudal fin; these, show best against a dark background. Some specimens lack the adipose fin (Fig. 6).

Hemigrammus ocellifer (Beacon-fish). One of the earliest-known and still most popular fishes. The upper half of the eye gleams red like fire, and is matched by a similar spot above a black patch at the base of the caudal fin. The male is distinguished by a small white spot at front of anal fin. Originally from South America, but most stock now home-bred; grows to one and a half inches long (see Plate 2).

Hemigrammus pulcher. A distinctive species from the Amazon, reaching about one and a half inches in length. The color is olive with golden reflections, and there is a conspicuous black mark along the lower half of the tail. The body is deeper than in other members of this genus (Fig. 8, j).

Hemigrammus rhodostomus (Red-nose). A black stripe along the middle of the tail, white and black markings on the caudal fin, and a reddish glow on the nose, distinguish this species. It comes from Brazil, reaches two inches.

Hemigrammus unilineatus (Feather-fin). A silver fish with conspicuous marking of the dorsal and anal fins in black edged with white. Hardy and very popular, it originated in Brazil; it reaches about two inches in length (Fig. 8, K) .

Hyphessobrycon fiammeus (Flame-fish). A favorite aquarium fish, growing to one and a half inches in length, from streams near Rio de Janeiro. It is reddish, with silver head and abdomen; and has two dark bars at the shoulder. All the fins except the pectorals are red {sge Plate 2).

Hyphessobrycon heterorhabdus (Belgian-flag Tetra). A conspicuous stripe of red and yellow above black, from head to tail along the side, gives this fish its popular name. The upper part of the eye is red. From the Amazon region, growing to one and a quarter inches long (Fig. 8, L).

Hyphessobrycon innesi (Neon-fish). Most brilliant of the group— white abdomen, scarlet tail (but not caudal fin) and a stripe of iridescent blue or green (varying according to the light) from the eye to above the tail, looking like a strip of neon lighting. The colors fade with fear, cold, or at night. Found in the upper reaches of the Amazon, growing to a little more than an inch. Always rather expensive because difficult to breed, but is hardy and may live for ten years (see Plate 2).

Hyphessobrycon pulchripinnis (Lemon Tetra). A transparent fish, faintly yellowish, with a broad black edge to anal fin, the front rays of which are brilliant yellow; dorsal fin similarly marked, but the tip whiter; upper half of eye red. A pretty species, an inch or more long, from the lower Amazon (Fig. 8, M).

Hyphessobrycon rosaceus. A spectacular and excellent aquarium fish. Generally reddish in color, with rose-red splashes in the pelvic, anal and caudal fins; the dorsal fin is large, mainly black with a white edge, and is higher and more pointed in the male, red tipped in the female. Found in Brazil and Guiana, it reaches two inches in length (see Plate 2).

Hyphessobrycon scholtzei. Silvery, with an intense black stripe from shoulder to end of tail, joining a large black patch on the caudal fin. An excellent aquarium fish from the lower Amazon, growing to two and a half inches long, and easily bred (Fig. 8, p).

Hyphessobrycon serpae. Very similar to the preceding, but the lower fins and caudal fin are almost entirely deep red, and there is a black vertical mark at the shoulder (Fig. 8, N).

Moenkhausia oligolepis. Silvery, each scale edged with black; a golden spot on top of tail behind adipose fin, and a large black blotch at root of caudal fin. Originally found in Brazil and Guiana; grows to four inches long, but at that size tends to bully other fishes (Fig.)

Moenkhausia pittieri. Silvery, with greenish reflections. Chief beauty is the large dorsal and anal fins; upper half of eye bright red. Two inches or more in length; comes from Venezuela (Fig. 9, B).

Mannaethiops unitaeniatus. One of the few African Characins suitable for the aquarium; most of the others are too large or voracious. The body is pinkish, with a lateral black stripe above which is a shining golden line; some red in the fins; front edge of dorsal fin black. Peaceful and hardy, growing to about three inches (Fig. 9, c).

Nannostomus beckfordi (also known as N. anomalus). An intense black band from tip of nose to end of tail, with a brilliant golden line above it; under parts white; some red in the fins; pelvic and anal fins tipped with white in the male (Fig. 9, D). When resting in the dark the horizontal stripe fades, and is replaced by three broad vertical bands, as can be seen by switching on the light suddenly. The same may be said of:

Nannostomus marginatus, which has two dark stripes along the side separated by a golden line, and

Nannostomus trifasciatus, which has the yellow stripe much wider than the black ones; the male has a line of red spots along the yellow band. There is some red in the fins of this species, and it grows a little larger than the others (nearly two inches). All these beautiful species come from Brazil.

FIG. 9

A) Moenkhausia oligolepis ; B) Moenkhausia pittieri ; c) Nannaethiops
unitaeniatus; D) Nannostomus beckfordi; E) Poecilobrycon auratus;

F) Thqyeria sanctae-mariae

Poecilobrycon auratus (Pencil fish). Rather similar to the preceding, but the lower dark band is broad, below the middle of the body, and is continued on to the lower lobe of the caudal fin; a spot of red on the anal fin. There is no adipose fin (Fig. 9, E). A very similar species is:

P. unifasciatus, but this has the lower lobe of the caudal fin red at base and black and white at tip.

These fishes tend to tilt head upwards when at rest, but take a horizontal position when moving forward. They and the species of Nannostomus have very small mouths, and must be fed accordingly. They grow to about two inches long, and are from the Brazilian region.

Pristella riddlei (Enamel-fin). An old favorite in the aquarium, and still one of the best. Translucent olive-tinted body with silvery abdomen, and a dark spot on the shoulder. Dorsal, anal and pelvic fins with black blotch and conspicuous enamel-white tips; caudal fin reddish. Common throughout north-eastern South America, it rarely exceeds one and a half inches in length (see Plate 2).

Thayeria sanctae-mariae (Oblique-fish). A silvery fish shaped like a Hemigrammus, with an intense black stripe from the top of the head to the lower lobe of the caudal fin, which is longer than the upper. This species tilts head upwards when resting, but swims horizontally. It comes from the lower Amazon, and reaches two and a half inches in length. It is better known to aquarists as Thayeria obliqua, a name applicable to a similar, but different, species (Fig. 9, F).

The Cyprinids

An immense group of typically freshwater fishes, found throughout North America, Europe, Asia and most of Africa. They have no teeth in the jaws, and no adipose fin. Many of them have small "feelers", known as barbels, at the corners of the mouth; they have given the best-known group "the Barbs" its popular name, though some of the species lack them.

Barbus conchonius (Rosy Barb). Silver, with dark edges to the scales, and a black spot on the side of the tail. The male is usually the smaller, has darker borders to the fins, and becomes flushed with rosy red when in breeding condition. No barbels. Native of India, but for many years bred in captivity, reaching a length of over three inches (Fig. 10, A).

Barbus cumingi. Similar to the above, but the black on the tail forms a vertical bar, and there is another near the shoulder. The scales are larger and fewer. The male has bright red dorsal and anal fins. Comes from Ceylon, and does not exceed two inches in length (Fig. 10, B).

Barbus everetti (Clown Barb). A rather long-bodied, coppery species with red fins; there is a black vertical bar behind the head, a patch at base of dorsal and a large spot in middle of side (remains of a second bar), a third bar, rather broken, across the tail above the anal fin, and a black spot at the base of the caudal fin. A pair of rather long barbels. From Malaya and Borneo, it grows rather large— four inches or more (Fig. 10, c).

Barbus fasciatus. A very handsome silvery fish with five or six stripes from head to tail. Two pairs of rather long barbels. Comes from Malaya, Sumatra and Borneo, growing to three inches or more (Fig. 10, D).
Barbus fasciolatus. An olive and silvery fish, with twelve short, narrow vertical bars on side, one at the shoulder and one at the end of the tail being more intense. Two pairs of barbels. This little fish, reaching about two inches long, is from Africa, and is sometimes confused with B. semifasciolatus.

PLATE I

PLATE 2

PLATE 3

PLATE 4

FIG. IO

Barbs, A) Barbus concJwnius; B) B. cumingi; c) B. everetti; D) B. fasciatus; E) B. lateristriga; F) B. nigrofasciatus; G) B. oligolepis; H) B. phutunio; J) B.aemifasciolatus; K) B. tetrazona; L) B. ticto; M) B. titteya C

Barbus lateristriga (Spanner-barb). Two black vertical bars on the front half of the body and a horizontal one along the side of the tail, suggest an adjustable spanner or wrench, hence the popular name. One pair of slender barbels. Comes from the same area as B. everetti, grows as large, and has been confused with it (Fig. 10, E).

Barbus nigrofasciatus (Ruby Barb). A deep-bodied species, each scale with a jewel-like gleam. Five rather diffuse, black vertical bars, the first across the gill-cover. In good conditions the front part of the male becomes ruby-red, and the black more intense. From Ceylon, growing to two inches long (Fig. 10, F).
Barbus oligolepis (Chequered Barb). A silvery Barb with large scales, two rows of which have the outer part black, giving a chequered appearance. The fins are reddish in the male and yellow in the female; the dorsal fin has a black margin, and in the male the anal fin also. One pair of very small barbels. A lovely species from Sumatra, growing to two inches in length (Fig. 10, G).

Barbus partipentazona. A small silver Barb from Malaya, with five black cross bars, the first through the eye, the last at base of caudal fin; the middle one is on the dorsal fin, and scarcely passes on to the body; a dash of red in the dorsal fin of the male. Pure examples of this species are not often seen, as they have been hybridized with B. tetrazona.

Barbus phutunio. A small glittering Barb, with a dark spot at the shoulder and two on the tail, all three surrounded by a kind of halo of pale gold; fins reddish. Comes from India, and seldom exceeds an inch in length (Fig. 10, H).

Barbus semifasciolatus. Large, shining scales, a greenish stripe along the side overlaid with six or seven narrow cross-bars which are somewhat broken up, characterize this species. There are two small barbels. Grows to three inches in length, and comes from South China. A golden variety is known as B. schuberti, a name that has no validity (Fig.io,j).

Barbus tetrazona. Like B. partipentazona, but the body color more golden or pinkish. In pure-bred examples the middle stripe (on the dorsal) is practically continuous with the fourth stripe which extends on to the anal fin. The dorsal, anal and caudal lobes all show bright red. A native of Sumatra, more colorful than B. partipentazona, but crossed with it to the detriment of both. Aquarists getting these fishes true to type should prize them and keep them separate (see Plate 2, and Fig. 10, K).

Barbus ticto. Silvery, with a black vertical bar at the shoulder, and another on the tail, above the anal fin; the second has a "halo" of golden hue. The dorsal fin has dark spots, and in the male is bordered with bright red. Grows to three inches or more, and comes from India (Fig. 10, L).

Barbus titteya (Cherry Barb). A very beautiful species, with a black stripe from tip of snout to end of tail, above which is a broad yellow stripe; some red in the fins. The whole body and head and the caudal fin of the male may be flushed with ruby red, which becomes very brilliant at breeding time. Comes from Ceylon, reaching about two inches in length (Fig. 10, M).

Brachydanio albolineatus (Pearl Danio). A streamlined, fast-moving fish with iridescent shades of pink, blue and yellow giving a pearly lustre; looks best in a small shoal, and with the light coming from the front of the tank. A pair of long, slender barbels. Reaches a length of about two and a half inches, and comes from Burma and Siam.

Brachydanio rerio (Zebra Fish). Yellowish, with deep metallic blue horizontal bands from behind the head, extending on to the caudal fin. A pair of long, slender barbels. An old favorite from India, growing to about one and a half inches, very active and easily bred. Very prone to deformity, and those with a "bent" look should be rejected. A similar, rather smaller species, with the lowest stripe broken into spots, and only one stripe passing on to the caudal fin, is B. nigrofasciatus, occasionally available {see Plate 2).

Danio malabaricus (Giant Danio). A superb fish, silvery, the sides with two or three horizontal bands of alternating yellow and metallic blue; the bands are rather broken on the shoulder, and one extends on to the caudal fin; dorsal, anal and pelvic fins reddish. Sexes difficult to distinguish, but the lower jaw of the male juts forward slightly, and the female is usually the larger. Grows to four inches in length. Native of India. A similar species from Ceylon, called D. devario, has a deeper body, and the blue bands forming distinctly vertical stripes at the shoulder (see Plate 2).

Esomus danricus (Flying Barb). A swift, surface-swimming fish, very graceful, with black horizontal stripe above which is a golden line. A very long pair of slender barbels. A great jumper, so a cover on the tank is essential. Native to India and Burma, growing to four inches long. Another species, E. malayensisy is smaller, with a conspicuous spot on the tail, and the lateral stripe hardly developed (Fig. 11, A).

Rasbora daniconius. An olive-colored fish with white underparts; a black line along the middle of side, thinly edged with golden; fins yellowish. This may be taken as typical of a number of species Rasbora which may be available from time to time, varying in details as to the black stripe, and sometimes a little more colorful; such are R* einthoveni, R. lateristriata, R. leptosoma, R. meinkeni, R. panciperforata, R. rasbora, and R. taeniata. All are good aquarium fishes from the Indo-Malayan region, usually two or three inches long (Fig. 11, B) .

Rasbora dorsiocellatus. A dainty little species (about one and a half inches long) with a large black spot surrounded by white on the dorsal fin. With it may be mentioned R. maculata, which is similar in size and shape but has a large black spot on the shoulder, one at the end of the tail, and small ones on the dorsal and anal fins. Both are from the Malayan region (Fig. 11, c).

Rasbora heteromorpha (Harlequin-fish). Most famous of the genus, differing from most in the deep body and unusual pattern. The front part of the body is silvery, the hind part red. The tail region is marked by a wedge or triangle of black; middle of dorsal and front of anal red; the male is distinguishable, at least at breeding time, by gleaming golden line above the black. The eggs are sticky, and attached underneath the broad leaves of plants like Cryptocoryne; but the species is not easy to breed, and is never cheap. Native to Malaya and Sumatra, growing to one and a half inches long {see Plate 2).
 
A) Esomus danricus; B) Rasbora daniconius; c) Rasbora dorsio-cellata; D) Rasbora tnlineata; E)  Corydoras julii; F)  Corydorasoeneus;    G)    Corydoras   paleatus;    H)    Kryptopterus   bicirrhus; j) Otocinclus affinis

Rasbora tnlineata (Scissors-tail). Chiefly remarkable for the markings on the caudal fin, each lobe being cross-striped with orange, black and whitish; these draw attention to the opening and closing action of the fin, rather like a pair of scissors. Grows rather large, specimens of four or five inches being usual; comes from Malaya (Fig. 11, D).

Tanichthys albonubes (White-cloud Minnow). A beautiful little fish, ideal for the aquarium. A dark stripe along the side has a golden one above it (in very young fish gleaming green, like the Neon fish); dorsal and caudal fins have a bright red patch at center and a yellowish border. The male is more intensely colored, and generally more blue than the female. The length is seldom more than an inch. This species was discovered in a stream on White Cloud Mountain (little more than a hill) near Canton, China. The water of the stream is quite cool, and the fish is therefore not strictly tropical; it can withstand temperatures as low as 4O°F. But it shows most color and breeds best at about 7O°F. {see Plate 2).

The Loaches

These are related to the Cyprinids, but are usually longer in the body, and have more barbels. The air-bladder serves as an accessory breathing organ, and they often dash rapidly to the surface for a gulp of air. They are useful "scavengers", foraging in the sand with their "feelers" for scraps; when in a tank with many other fish, however, care should be taken to ensure that they get enough food.

Several kinds of Loaches are seen from time to time, but the only one generally available for the tropical aquarium and very popular is:

Acanthophthalmus semicinctus (Half-banded Coolie). A very elongated *'worm-like" fish, salmon-pink with a series of broad, saddle-like dark brown patches extending half-way down the sides, in the middle of each of which, in the back, is a white spot. Spends much of its time under stones. If a number are placed in a large tank, with cover to which only they have access, they will breed secretly, and the offspring will not make their appearance until well-grown; a large ear-shell placed concavity downwards is good for this; the loaches go in and out through the small holes in its side. A. semicintus comes from Malaya; a related species, A. kuhli, with bands extending right across the body, is from Java and Sumatra, and there are others from Siam, Borneo, etc. (see Plate 2).

The Catfishes

These, like the Loaches, have six or eight barbels round the mouth, sometimes growing quite long; they have a rather large, bony head, an adipose fin, and the first ray of the dorsal and of the pectoral fins is strong, with a saw-like edge.

In the tropical aquarium the most popular are the Armored Catfishes of the genus Corydoras; these have two series of bony plates along the side, overlapping in the middle line, like a suit of armor. They are attractively-shaped, busy and often dash to the surface for a bubble of air, having an accessory breathing organ above the gills. They are found only in tropical America. About 10 of the thirty-odd species have been seen in aquaria, but only three or four are usually available.

Corydoras julii (Leopard Catfish). Gray, with a triple black stripe along the side, and numerous spots above it; a large black blotch on the dorsal fin, and narrow stripes across the caudal fin. Grows a little more than two inches long, comes from Brazil (Fig. 11, E) .
Corydoras melanistius. Gray, with numerous small black spots and two broad black vertical bars, the first through the eye and the second from base of dorsal fin. Comes from British Guiana and Venezuela, and grows about two inches long (see Plate 2).

Corydoras oeneus (Bronze Catfish). Olive back, pinkish underparts, and a large bronze-green patch, with blue reflections, on the side; no markings on the fins. Comes from the island of Trinidad, and may grow to three inches long (Fig. 11, F).

Corydoras paleatus. Commonest of the group, usually obtainable. Yellowish, with a few metallic reflections, marbled with bluish black. Native to the southern part of Brazil and Argentina, but available stock is often aquarium-bred; grows to about two and a half inches (Fig. 11, G).

Kryptopterus bicirrhus (Transparent Catfish). One of the oddities among fishes. A rather long fish, very compressed from side to side, with a minute dorsal fin and a very long anal fin and very long, sensitive barbels. It is quite transparent, so that the skeleton is visible, only the forwardly-placed internal organs being opaque, in a silvery sheath. An East Indian fish worth having if there are not too many boisterous fishes in the same tank. Grows to about two and a half inches long (Fig. 11, H).

Otocinclus qffinis. A small Catfish with short barbels and the mouth underneath the head; the lips form a sucking disk by which it can attach itself to the glass of the tank or elsewhere. It is a first-class scavenger, cleaning plants of algae, and rocks and sand of scraps which would otherwise decay; it even cleans the surface of the water by swimming along it upside down. A little delicate, needing vegetable matter (algae, finely-chopped spinach or lettuce). Comes from Brazil, and reaches two inches in length (Fig. 11, j).

The Gyprinodonts

These are related to the Livebearers already discussed, but all lay eggs in the usual manner, the anal fin of the male not being modified. They are something like the Cyprinids, but they have teeth in the jaws, the dorsal fin is usually much further back, and there is no visible lateral line (though often a stripe of color in that region). Many species are known, from the tropics of the world, of which about 40 have been seen in aquaria, including some of the most elaborately colored of freshwater species. Many of them, however, are specialists' fishes, and command rather high prices, so only the most popular ones are listed here. Most of them require a temperature about 7o°F.
Aphyosemion australe (Lyretail). A brown body with rusty spots, the fins of the male with an elaborate pattern of orange, blue and dark brown, those of the female plain. The male is also distinguished by the points on the fins, which develop with maturity. A West African species, growing to two and a half inches in length (Fig. 12, A).

Aphyosemion caeruleum (Blue Gularis). Body "shot" bluish, with irregular dark markings. The fins of the female are rounded, but the male develops points on the dorsal and anal, and three points on the caudal fin, which has a large patch of orange-red. Grows to four inches long, and should not be kept with very small fishes, for it may eat them; comes from West Africa (see Plate 2).

Aplocheilus lineatus (Striped Panchax). Body with metallic reflections of various colors, and six or seven narrow black vertical bars on rear part of body; vertical fins with red margins. Native of India, reaching a length of about three and a half inches, and inclined to bully other fishes (Fig. 12, B).

Aplocheilus panchax (Panchax). Body olive-green, variously overcast with shades of other colors; the dorsal, anal and caudal fins of the male with yellow or orange bands, the caudal with a narrow black edge. An East Indian species growing to two and a half inches long.

Epiplatys chaperi. Body olive-colored, with four or five black vertical bars in the hinder part; the male has metallic reflections of blue and gold, and a bright red chin and throat. The fins are rounded and plain in the female, but in the male the dorsal and anal fins are pointed, while the caudal fin has a point at the lower margin only; these fins are buff, with red speckling, and the lower margins of the anal and caudal fin are broadly black. A West African species reaching two inches in length (see Plate 2).

Jordanella floridae (Flag-fish). Much more deep-bodied than most of the family, this is sometimes mistaken for a Cichlid (q.v.). The body has greenish metallic reflections, and the scales are margined with red; these colors being much more brilliant in the male. There is a conspicuous black spot on the side. The male guards the eggs after they are laid (another resemblance to Cichlids). This fish is from Florida, and grows to more than two inches long. It is inclined to quarrel with other fishes (Fig. 12, c).

Oryzias javanicus (Medaka). An olive and silvery fish, with gleaming blue eyes, like a pair of lamps (it is often called Lamp-eyes). Peculiar in that the eggs when first laid hang from the female like a bunch of grapes. Easy to keep and breed. Gomes from Malaya and Java, growing to one and a half inches.
Pachypanchax playfairi. Body slender, yellow. The female has red dots on the sides and a black spot on the dorsal fin. The body of the male is richer yellow flushed with orange; lines of red dots follow the rows of scales along the body; metallic green spots on the dorsal and anal fins, which are edged with red. An East African species, reaching three and a half inches, which may attack other fishes (Fig. 12, D).
Rivulus cylindraceus. Body olive above, yellowish below, an irregular band of dark brown along the side; some spots of dark green and red on the male. Fins of male yellow, with red spots at base of dorsal and anal, and lower margins of caudal black. Female with a conspicuous black spot at upper base of caudal fin. From Cuba, reaching two inches in length. Other species of Rivulus, from the South American mainland, are sometimes available (Fig. 12, E).

FIG. 12

A) Aphyosemion australe; B) Aplocheilus lineatus; c) Jordanella floridae; D) Pachypanchax playfairi; E) Rivulus cylindraceus

The following species may conveniently be included here. They belong to Perch-like families, having the first part of the dorsal fin supported by stiff spines.

Ambassis lala (Glass-fish). Quite transparent, except for the silvery lining of the body-cavity, and the gill-covers. Four or five narrow vertical black bars on the side can be switched on or off; they usually show most at night, or when the fish is in trouble; the high spines of the first dorsal are black; male more yellowish in body, with distinctly bluish margin to soft dorsal and anal. Comes from India, reaching about one and a half inches long (see Plate 2).
Melanotaenia maccullochi (Rainbow-fish). A silvery fish with dark stripes along the body, a red spot on the gill-cover, a red caudal fin and red margins to the other fins. Another species, less often seen nowadays, is M. nigrans, with red and yellow stripes along the body— a very colorful fish. These are from Australia, and grow to about three inches long (Fig. 13, A).

Scatophagus argus (Scat). A deep-bodied, yellow or bronze-colored fish, with black spots. The yellow with large spots, from India, is prettier than the bronze one with small spots, from the Indonesian region. One with a good deal of red at the edges, and a tendency to vertical stripes (the Tiger Scat), may be a different species. These are exceedingly attractive fishes which can be kept in freshwater, but do better with a little salt. Fond of vegetable matter, but will eat anything. The bigger the tank, the bigger they will grow (Fig. 13, B).

The Labyrinth-Fishes (see Plate 3)

These are so called because of an elaborate structure situated above the gills, known as the labyrinth organ, which enables them to breathe atmospheric air; this seems to be quite essential to their well-being, and if they are by any means prevented from taking a mouthful of air now and again at the surface they do not survive.

Another popular name for them is "bubble-nesters", on account of the habit, which most of them have, of blowing a mass of air-bubbles at the surface of the water, among which the eggs are laid. This "nest" is made by the male, and after a beautiful and active courtship has resulted in the fertilization of the eggs, he guards them carefully, replacing any that fall from the nest, and later, when they hatch, protecting them vigorously against all dangers, even driving the female away. These interesting fishes belong to a family called Anabantidae, and are, therefore, referred to as Anabantids.

Another of their unusual features is the number of spines in the front part of the anal fin, sometimes even exceeding the number in the dorsal. It can be stated as a general rule for all of them that the soft dorsal and anal fins are longer and more pointed in males than in females.

They are, generally speaking, peaceful towards other fishes, even when much smaller than themselves, and can thus be included in the "community tank". Most of them are colorful, adaptable, and easily fed. So it is hardly surprising that they are among the most popular of aquarium fishes.
Anabas testudineus (Climbing Perch). A brown fish, often with a black spot at the end of the tail, but the markings varying. Sometimes shy, not remarkable for its beauty, but interesting for its habits. It can live a long time out of water, and can "walk" over land by means of its saw-edged gill-covers. If kept in a tank half water and half land, it can be trained to come ashore for attractive titbits. It does not make a bubble-nest, and does not pay much attention to the young; it comes from India and the East Indies, and may grow to five inches in the aquarium (much larger in the wild state).

Betta splendens (Fighting-fish). Good males of this species are spectacular in forms and color. They should have a tall, pointed dorsal fin, a long oval caudal fin, and a very large, broad anal fin.

FIG. 13

A) Melanotaenia maccullochi; B) Scatophagus argus ; c) Badis badis ; D) Polycentrus schomburgki; E) Tetraodon fluviatilis

The color should be either entirely deep blue, entirely light blue, entirely blood red, or with a cream-coloured body and red fins. The pelvic fins remain obstinately red in all varieties. Unfortunately, a large number today are nondescript mixtures of red and blue, often a dull brown body, and the fins are poorly developed. This is due to negligent mixing of strains by aquarists more interested in quantity than quality. The difficulty is in the female, who is always more modestly colored and has quite small fins, so it is difficult to ascertain her ancestry. For these reasons, good specimens are never cheap. The best way to see the full beauty of Betta is to keep two males in two adjoining tanks, so that they see each other through the glass. They will then spread their fins and show their color, for they are born fighters. On no account must two males be put in the same tank, for they will tear each other to pieces. Likewise the male is inclined to bully the female, and she should be kept separately until breeding time. The male makes a bubble-nest. Because they can use atmospheric air, these fishes can be kept in much smaller aquaria than most others, or in a large tank divided into small compartments by sheets of glass. They come from Siam, where they are bred for their fighting qualities, contests being staged. Our stock is bred rather for its appearance, and fighting is discouraged. A body length of about two inches is usual.
Colis fasciata (Striped Gourami). A beautiful fish, golden brown with deep blue stripes across the sides. The rear part of the dorsal and anal and the caudal fin are orange, and there is a red edge to the anal fin. The pelvic fins form a pair of very long, slender "feelers", which are used for exploring the surroundings. A bubble-nest is built. An Indian fish growing to four inches or more in length, but peaceful towards other fishes.

Colisa lalia (Dwarf Gourami). Like the preceding, but much smaller, the body being metallic blue, with more or less vertical rows of vivid red spots forming bands which do not, however, extend on to the head or abdomen; the soft dorsal, anal and caudal fins have an elaborate pattern of red or blue. The "feelers" of the male are red. The colors of the female are much paler. Comes from India, growing to two inches long.

Macropodus opercularis (Paradise-fish). Alternate stripes of red and green, and a red caudal fin, in both sexes. At breeding time the male becomes brilliant, the female paler. A bubble-nest is made. From South-eastern Asia, it grows about three inches long, and is inclined to bully smaller fishes; kept apart, it gets tame, and is worth keeping.

Trichogaster trichopterus (3-spot Gourami). Rather heavily built fish, blue or grey with a number of darker, rather oblique cross stripes, a black spot at end of tail and another midway between it and the eye, giving a 3-spot effect; fins with pearly spots and sometimes some red dots. There is a rather beautiful fawn variety also. The sexes are similarly colored. A bubble-nest is made. Comes from Malaya, Indo-China and Sumatra, growing to a length of more than four inches. Small ones are suitable for the community tank.

Trichogaster leeri (Pearl Gourami). Similar to the preceding, but more gracefully formed. Grey, overlaid with close-set pearly spots on body and fins; a black stripe from tip of snout backwards, petering out towards the tail, appearing again as a black spot at base of caudal fin. In breeding condition the male has bright orange-red on lower head and rump. A very beautiful, gentle fish, but not so hardy as the 3-spot. From Malaya, Siam and Sumatra, growing to six inches long.
The Gichlids (usually pronounced Sick-lids) {see Plate 4)

These form a large family of freshwater fishes almost entirely confined to the South American and African continents. They are perch-like fishes which sometimes grow very large, and only a few of them are suitable for aquaria. Most of them care for their eggs and young in some way or another.

Aeguidens latifrons (Blue Acara). An olive fish with a brilliant metallic blue or green spot on each scale, as though spangled. A black blotch in the middle of the side and six or seven dark cross-bands which may disappear; the fins are reddish, with blue markings. At breeding time the sexes indulge in a tug-of-war, and if equally matched, they mate. The eggs are laid on a stone, or other hard surface, and the parents take turns in fanning them to aerate them; after hatching, the young are protected furiously against all comers. Needs plenty of room, is rather carnivorous, and should not be kept with another species. Comes from Central and South America, and grows to six inches long. Other species of Aequidens are sometimes available.

Apistogramma ramirezi (Dwarf Cichlid). A pretty bluish species with oblique dark cross-bars, two black stripes crossing at the eye, and the first spines of the dorsal fin rather long, forming a point, dark-colored; the lips are red. At breeding time the female gets a pink blotch on the side of the abdomen. The breeding habits are similar to those of the preceding species. This Venezuelan species does not grow longer than two inches, is peaceful and can be kept with other fishes.

Astronotus ocellatus (Marbled Cichlid). A fine fish, but needs a tank to itself. Body marbled with shades of brown and black, and often some bright orange-red spots and dashes; a black spot at the base of the caudal fin, surrounded by a shining ring of orange or red. A South American fish growing to eight inches long if given the space, and requiring plenty of live food.

Cichlasoma biocellatum (Jack Dempsey). A dark species, spangled all over with gleaming blue spots, and with a red edge to dorsal fin. The colors intensify with age, and as the fish lives for many years and grows to more than six inches long, it can be spectacular. It needs a tank to itself, when it becomes very tame and can be taught tricks. Breeding is like that described for Aequidens.

Cichlasoma meeku Body gray, with vague darker cross-bars, and a broken black band along the side; underparts red, becoming very brilliant at breeding time; a black spot on lower gill-cover, surrounded by shining green on gold; fins with red rays. A beautiful species from Yucatan, growing to about four inches long, and peaceful enough to trust with other species if not very small. Breeds in same manner as Aequidens.

Haplochromis multicolor (Mouthbreeder). A rather plain olive and silvery fish, with a dark line along the side and some vertical bars on the back; fins tinted with orange, and with some shining blue marks. It is chiefly remarkable for its method of protecting its eggs and young, which are carried about in the mouth of the female, who does not feed during this period. From North Africa, especially

Egypt, this species grows to about two and a half inches long, and can be kept with other species if not too small.

Hemichromis bimaculatus (Jewel-fish). A yery beautiful species, the olive-colored body being spangled with shiny blue spots and sometimes flushed entirely with bright orange-red; the fins are bordered with blood-red. But it is a very pugnacious fish, and will fight even with its own kind. It is included here only as a warning to the beginner not to buy it until he has enough experience. This is an African species, growing to four inches long.

Pterophyllum scalare (Angel-fish). Probably the best-known exotic aquarium-fish. Very decorative shape, silvery with broad black vertical bars, and some red in the eye; the long filaments of the pelvic and anal fins are bluish. Sexes alike. The eggs are laid on the broad leaf of a plant, or other vertical hard surface, and cared for in the Cichlid fashion.

This is a gentle species which can be kept with others, but it is not a beginner's fish, for it is difficult to keep and breed, being nervous in disposition and liable to refuse food. Everyone wants to keep Angels, but unless experience is gained first, disappointment will follow. These beautiful fishes are from the Amazon region, growing to ten inches deep in the wild state, but only half that size in the aquarium.

Three other Perch-like fishes which care for their young may be mentioned. The first two belong to the family Nan-didae; they are pretty fishes which eat only live food, but may be kept with other species of the same size. They like to breed in secret, generally being given a flower-pot inside which they lay the eggs; the female must be removed afterwards, the male guarding the eggs and fanning them with his fins.

Badis badis. A fairly slender fish with a few cross-bands, that undergoes many color-changes from dark brown to pale yellow or orange. Comes from India, and grows to about two and a half inches (Fig. 13, c).

Polycentrus schomburgkii. Also very changeable in color from black to pale brown, overlaid with black or pale blue spots which may disappear; the caudal fin is so transparent that it is often invisible. A South American species reaching two and a half inches in length (Fig. 13, D).

Brachygobius xanthozonus (Wasp Goby). Bright pale golden, with black fins and four broad dark bands across the body. The pelvic fins are joined together to form a sucking disk, by which the fish can attach itself to the rocks or the glass at odd angles. The male fans and protects the eggs, which are laid underneath a flat stone or in a flower-pot. This pretty species, only one and a half inches long, comes from Malaya and the East Indies (see Plate 2).

Tetraodon fluviatilis (Puffer-fish). Most of the Puffer-fishes are marine, but this one, and a few others, inhabit fresh water. This species from India grows to only about two and a half inches long, and is shining yellow-green on the back, with black spots, and white underneath. When alarmed, the Puffer inflates itself with water into a globular form, small prickles protruding from the skin. The best performers do not usually live long, because they are highly strung and so easily frightened. Normal specimens are easy to keep and live a long time, but must have fresh or live foods; they are specially fond of crushed snails, chopped shrimp and shredded raw fish (Fig. 13, E).

B. Cold-Water Fishes

These are fishes which require no special heating in an ordinary home aquarium. But this does not mean that temperature is not important. Their temperature range is lower, and in the summer there may be a problem caused by too much heat, but that will be dealt with in the chapter on maintenance. Also, they are just as susceptible to sudden changes of temperature as any others, for the reason already explained. This is why keeping Goldfish in small bowls, when the water must be changed frequently, so often proves fatal.

Generally speaking, cold-water fishes require more oxygen, and therefore more water-surface, than tropicals. They are more liable to disease. They usually spawn less frequently and take longer to grow to maturity, so that breeding needs time and patience. Nowadays, too, it is less easy to get good stock to begin with, and it is often expensive. That is why it is better to gain experience with tropicals first. But, just because of the difficulties, success with cold-water fishes is more rewarding in the end, and the man who achieves it can claim to be a real aquarist.

Despite this, many aquarists mistakenly try to begin with cold-water species, imagining that they can then get some fish from a nearby river and put them in the tank, thereby saving money. Fishes thus taken from the wild seldom thrive, however, unless they are taken at a very small size; even then they are very prone to ailments and may bring parasites with them. Very few of our native fishes are really suitable for aquaria; some do better in ponds, but are then more difficult to see, and more exposed to enemies. On the whole, therefore, preference is to be given to cultivated stock, and only a few of our native species will be found in the list which follows.

In this list, unlike those of the tropicals, the popular names are given first, since they are better known than the scientific ones.

The Goldfish

This must be given first consideration, for it is still the finest cold-water fish for the aquarium.

Originally, the Goldfish (Carassius auratus) was a rather dull olive-colored fish inhabiting the temperate regions of Asia from the Caucasus eastward, and was well known to the Chinese from very early times owing to the ease with which it could adapt itself to their ornamental pools. They found that some had a tendency to red or golden colors (such varieties may turn up in many other kinds of fishes) and naturally selected these because they were more attractive. By such selection over many hundreds of years a number of varieties, fantastic not only in color but in shape also, were developed in China and later in Japan. Goldfish have, during the last two centuries, found their way into most parts of the world through the agency of man. A very large proportion of those seen nowadays in Britain have been bred in Italy, where millions are raised in large ponds; but these are, of course, a very mixed lot, and seldom of good quality. A study of the numerous varieties, with a view to selecting the *best and standardizing them, is now being carried out by the Goldfish Society of Great Britain.

The ordinary kind, or "common goldfish", is still very popular. It has shining, metallic scales and the fins are not specially enlarged; it may be deep red, golden, brassy yellow, silver, or variegated with black patches; really good examples, with well-proportioned shape and rich colors, are rare, but when found are among the most beautiful of fishes.

The shubunkin. A very popular variety, which differs in having some of the fins, especially the caudal fin, enlarged, and the scales so transparent as to be invisible; the color is variegated, and blue is specially valued (Fig. 14, A).
More fancy varieties are those which have a deep, almost globular body, and the caudal and anal fins double. These are broadly classified as "twintails".

The Fantail. This has metallic scales, and the double caudal fin is held aloft, fan-like. Usually it is plain red or golden (Fig. 14, B).

The above varieties are very hardy, and can be bred and reared in outdoor ponds without difficulty. The remainder to be mentioned are more delicate, and are more particularly aquarium fish.

The Lionhead is like a fantail, but the skin of the head is enlarged into a curious, deep red growth like a big raspberry (known as the bramble-head development) and the dorsal fin is missing. Good lionheads are scarce and therefore expensive (Fig. 14, c).

The Veiltail has transparent scales and variegated coloring like the shubunkin, but has a globular body, and the double caudal fin is very large and drooping (Fig. 14, D).

FIG. 14

Goldfish varieties, A) Shubunkin; B) Fantail; c) Lionhead; D) Veiltail; E) Oranda; F) Moor

The Oranda is a Veiltail with a bramble-head, and usually has metallic scales (Fig. 14, E).

Some of these fancy varieties may have "telescopic eyes", that is, the eyes bulge as more or less spherical projections from the head. This character is always desirable in:

The Moor, which is a black variety of the Veiltail; its body and fins should be entirely velvety black, without metallic reflections (Fig. 14, F).

The "metallic" effect of the scales of Goldfish is due to a layer of reflecting tissue close to the surface of the skin; when it lies a little deeper it imparts a pearly lustre to the fish called "nacreous"; and when very deep it gives no shine at all, and the skin is then called "mat"; the reflecting tissue combined with black pigment gives the much-prized blue effect.

The twin-tail varieties should always be examined closely to be sure that they have a double anal fin as well, for a single anal fin is considered a fault; the two halves of the caudal fin must also be completely separate.

It is not easy to tell the sex of Goldfish until breeding time—in the Spring, when the male develops a number of hard pimple-like growths called nuptial tubercles on his snout and gill-covers. The female is usually distinguishable, when looked at from above, by being rather more bulged on the left-hand side than on the right. When placed together the male chases the female, nudging her with his snout, and the eggs are deposited and fertilized among a mass of fine-leaved plants—such as Myriophyllum or Fontinalis, which should have been provided for the purpose. This behavior requires a good deal of room, and a large tank, or preferably a pond, is necessary. The parents will eat their eggs, so must be removed after spawning. The young ones can be raised in much the same way as described for other egg-layers in Chapter Nine. For the first few months they are dull olive-brown like their original wild ancestors, and do not show any bright color until about a year old; some never get color at all, and are usually weeded out, though they carry the color in their hereditary make-up and if bred with knowledge may produce well-colored offspring.

Goldfish take a wide variety of foods, and are particularly partial to small earthworms. They also require a proportion of vegetable matter, ordinary duckweed (Lemna) being a favorite. They are not good fishes for a decorative aquarium, as they tend to stir up sediment, uproot and damage plants.
The Crucian Or Prussian Carp (Fig. 15, A)
Closely related to the Goldfish, this fish (Carassius carassius) is native to the waters of western and central Europe. Some of the undesirable features of Goldfish are supposed to be due to cross-breeding with this fish. It is distinguished by the dorsal fin, which has a convex margin (concave or straight in Goldfish), by the rather larger head with straighter profile, and slightly smaller scales. The color is always bronze or olive-brown.

The Common Carp (Fig. 15, B)

Popular writers often state erroneously that the Goldfish is a golden variety of the Carp. The true Carp (Cyprinus carpio) is, however, quite different, and can be distinguished at once by the pair of barbels at the corners of the mouth. It is ordinarily a brown or bronze-colored fish, sometimes with a few scales along the side greatly enlarged. There is a golden variety called Hi-goi by the Japanese, also white and silver forms. Strictly speaking, however, it is not an aquarium fish, for it grows very large and is best kept in a pond. It is among the most hardy of fishes, and lives for as long as 40 years under good conditions.

FIG. 15

A) Crucian Carp; B) Common Carp; c) Golden Orfe; D) Golden Rudd

The Bitterling (Rhodeus amarus)  (Fig.  16, A)

This is a small European fish not seen often enough, for it is very attractive in appearance and has interesting breeding habits. Normally it is silvery, with a bluish band along the side; it grows to about three inches long. At breeding time, however, the male acquires beautiful metallic tints of various colors. The female develops a long ovipositor (breeding tube), and should then be provided with a specimen of the Painter-mussel (Unio pictorum), between the valves of which she will deposit the eggs. In nature the mussel responds by sending forth its young to cling to the skin of the fish, thus ensuring their dispersal to other beds. After several weeks the young bitterling, which have hatched within the shell, are ejected to seek their fortune. Needless to say, to observe this performance the species should have a tank to itself.
The Golden Orfe (Idus idus) (Fig. 15, c)

A                                 B

FIG. 16

A) Bitterling laying eggs in mussel; B) Sticklebacks with nest

The Ide is a silvery fish found wild on the continent of Europe; only its golden variety is used by aquarists. This is a beautiful shining pinkish-gold fish, sometimes with small black spots on the back. It is most suited for ponds, but small ones can be kept in aquaria for a while. They do not tolerate high temperatures, and want a lot of oxygen. In a pond they grow to about a foot long and are known to reach an age of 15 years. The breeding habits are much like those of the Goldfish, from which this fish can be distinguished by its slender form and much smaller scales.

The Golden Rudd (Scardinius erythrophthalmus) (Fig. 15, D)

A beautiful golden variety of a fish which is found wild in British waters. It is one of the few native-species which do well in aquaria, where it grows to about six inches long. In ponds it grows larger. It is a handsomely shaped fish with scales, red fins and a gleaming red eye. It takes most kinds of food and is reasonably hardy, but is not likely to breed in a tank.

The Stickleback {Gasterosteus aculeatus) (Fig. 16, B)

Given a tank to itself, this, the common "tiddler", is one of the most interesting of aquarium fish. It grows only to two inches long, but is pugnacious towards others much larger than itself. It has three sharp spines on the back, and each pelvic fin consists of a similar spine; these are its weapons. In the spring the male is distinguished by its bright red throat and belly, and shining green sides. He should be given several females in his tank, and there should be plenty of fine-leaved plants. He will then construct a nest of plant-debris, which he cements together with a secretion from the kidneys. Then he entices the females to lay their eggs in the nest, and afterwards guards them, and the young ones, fiercely; even the females dare not go near him then. In a large tank two males can be kept; they then build in opposite corners and each defends his own territory.
By giving it a little warmth during the colder months the Stickleback can sometimes be induced to breed twice or more a year in the aquarium, as do some of the "tropicals", and it displays brighter colors at the higher temperatures.

The Sunfishes

In the freshwaters of North America are found a number 01 species of Sunfish. These should be treated in much the same way, apart from temperatures, as Gichlids of South America. They are carnivorous, mostly rather belligerent, are hard on plants, and care for their young. Those most likely to be found are:

Black-banded Sunfish (Mesogonistius chaetodori). A delicate and very pretty little species, peaceful with its fellows, and quite the best aquarium-fish in the family. The black bands, alternately complete and broken, arranged vertically across the silvery-white body, have caused it to be called the "cold-water angel-fish". It is not as hardy as the others, but it does not need high temperatures (Fig. 17, A).

Common Sunfish (Lepomis gibbosus), growing to about six inches long in aquaria, beautifully variegated with a chequered pattern of dark brown and shining blue-green, and with a deep red spot on the lower gill. We call this fish the Pumpkinseed. It gets very tame and shows much intelligence (Fig. 17, B) .

Diamond Bass (Enneacanthus obesus), one of the smaller species, between two and three inches long, is docile, and it is possible to keep several in one tank. This is a lovely gray fish with shining spots over body and fins (Fig. 17, c).

Peacock-eyed Bass (Centrarchus macropterus), another small species, more beautiful when young, as there is then a black spot with a shining edge on the dorsal fin (Fig. 17, D).

Rock Bass {Ambloplites rupestris), somewhat similar to the Common Sunfish in appearance, but with a rather longer body, less metallic color, and a bright red eye. It must be kept alone, and grows quite large.

FIG.  17

A) Black-banded Sunfish; B) Common Sunfish; G) Diamond Bass; D) Peacock-eyed Bass; E) American Catfish

Finally, mention should be made of the American Catfish (Ameiurus nebulosus) which sometimes appears in dealer's stores. It is dark above, pale beneath, with a smooth sinuous body and long "whiskers" round the mouth. Like the tropical catfishes it is a scavenger, and can be kept with other species, but it will not thrive on scraps alone, and should be fed with earthworms, etc. It is nocturnal in habit, and therefore not a good show-fish; it does not breed in an aquarium, and is not hardy enough to remain in a pond during the winters (Fig. 17, E).

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