Breeding Fishes

If you begin, as advised, with a few Livebearers, it probably won't be long before one of the females has a brood of youngsters. In an ordinary community tank most of these will promptly be eaten by the others, unless there is a very thick screen of plants for their protection. However, this event may inspire you with a desire to breed them more success fully.

In a well-established tank healthy fishes of most kinds will go through the ritual of reproduction, but the chance of any outcome from this is very small in a community tank. It can be laid down as an axiom that you cannot breed fishes with only one tank. I would say that the minimum requirement is three, though when hard pushed it is possible, with a little scheming, to manage with two.

Many aquarists whom you will meet in clubs or at shows will tell you "I have bred this species and that species".  Sometimes, of course, their pride is justified, but very often the breeding has been very little of their doing. If all these people really bred fish properly we should have far more good stock than we have.

There is rather more to breeding fishes than just putting them together in an aquarium and leaving them to get on with it. That is just letting them breed—a different thing from breeding them.

First of all, it is necessary to get the best examples of the species that you can find. Choose your fishes for color, size and shape. A number of aquarium fishes, particularly Live-bearers, have been so modified by selective breeding that they bear little resemblance to the wild form.

With Livebearers, the large females you get will be already fertile, so the fullest-looking one of them should be in a tank to herself and well fed. The tank should have plenty of plants such as Myriophyllum and the floating Riccia. The temperature should be allowed to rise to 8o°F. In due course the young will be born, and the female should then be removed at once, and put in a tank by herself to recuperate. The young can be fed on dried egg, the finer grades of dried food, with the smallest kinds of live food.

Segregation Of Sexes

This is the stock from which you have to begin, and it is essential that the females should remain virgin until the right time. At first both sexes look alike, but after a while (varying in different species and breeds) the anal fin of the male begins to get more pointed, some of its rays thicken, and it assumes the shape of the gonopodium. At the first sign of this, the males must be separated from the females; if not, the damage will be done, for they are able to mate at a surprisingly small size. When fertilization takes place too soon, the individuals concerned remain small; moreover, when it occurs in a mixed brood you are robbed of the chance to pair up the individuals you want. No Livebearer should be mated until one year old.

This principle is to be applied to all fishes. Part the sexes as soon as possible, and keep them in separate tanks. Many of the egg-layers do not have obvious sexual differences, and the females can usually only be distinguished by the fullness of the body when they approach spawning condition. In some cases, however, it is worth-while looking at the fishes with a good light behind them, to show up the shape of the body cavity; in the females this is often broadly rounded at the hind end, and more pointed in the males. Looking at plenty of fishes at club shows and in other people's aquaria will help you to know the sexes of many fish.

If in real doubt, put half a dozen together and watch their behaviour; those that pair up should be selected and segregated. But even then you may be fooled, for fishes of the same sex occasionally court one another.

Once segregated, the sexes should be "conditioned", that is, given plenty of good food, in separate tanks, and should be grown as large as possible before being mated. Remember that the bigger the tank the larger they are likely to grow. With Livebearers, it is as well to select those that are growing fastest, and which show the characters you want to develop, and to dispose of the rest.

After this, timing is the important thing. The good aquarist breeds his fish at the time that he decrees. It should be arranged when you are likely to have time to attend to it, for it is advisable to keep a close watch on the tank during spawning.

Infusoria

A week or so before this, provision should be made for feeding the expected young. Get several large jars of water and place them in a warm place. Into each put a lettuce leaf, and a spot of water from the nearest piece of standing water—pond, ditch, rain-butt, etc. Soon the water will be cloudy, and after a few days you will see, with the aid of a magnifying-glass, a multitude of white specks moving about. These are infusoria, minute animal life which will be a valuable food for the youngsters.
Some kinds of fish need specially small species of infusoria, such as Euglena, and cultures of these can be bought; or tablets can be obtained which, when dissolved in water, produce them.

Brine-Shrimp

Another useful food for this purpose is Brine-shrimp; the eggs of these can be bought in packets or tubes, and if kept dry remain good for years. These are sprinkled thinly on the surface of water in which sea-salt (one tablespoonful per quart) has been dissolved, in a large shallow dish. After two or three days they hatch out, and the tiny shrimps can be netted and washed under a tap before being given to the young. Brine-shrimps can be taken almost immediately by newly-born Livebearers, but are too big for most egg-layers until they get past the infusoria stage. See page 120 for hatching Brine-shrimp with a sub-sand filter. For those that do not have the inclination or facilities for hatching Brine-shrimp, frozen newly-hatched Brine-shrimp are now available.

The Breeding-Tank

Meanwhile the breeding-tank must be prepared. This should be the largest available, and should have only six to eight inches depth of water in it. For egglayers, one end should be thickly planted with fine-leaved plants such as Myriophyllum,
 
Nitella, Fontinalis or Utricularia. Stones with filamentous algae are sometimes useful here. The idea is to provide cover for the eggs, so that the parents will not find them and devour them. It is often desirable to reduce the lighting, and to mask in the back and sides of the tank with dark paper.

Under no circumstances must snails, Cypris or other such scavengers be allowed in the tank. Some clean mulm dropped among the plants is a good idea.

The temperature of the breeding-tank should be the same as those in which the adult fishes are being conditioned, but after placing the selected pair of fish in it, the temperature should be raised to 8o° or 85°F. Sometimes it is useful to give two males to one female, to ensure fertilization of all the eggs. No food should be given to the parents while they are in the breeding-tank. They should be watched, without disturbing them, and as soon as the spawning performance is over (a frantic chase by the male in most cases) and they are resting exhausted, they should be taken out. Otherwise they will begin searching for food and devour some of the eggs.
If by any chance spawning behavior does not materialize, stop boosting the temperature and pour in a gentle stream of cool water from a height. This often stimulates them to activity.

Often it is best to place the fishes together in the evening, and if they have not spawned by bed-time, to leave them overnight. They are then likely to spawn early in the morning, and you should be up early to superintend it. If they have not spawned within 12 hours of being placed in the tank they probably will not, and it is best to separate them again, condition them for another week, and try again.

Of course, those with special breeding habits will be provided for according to their needs; Livebearers and the bubble-nest builders, whose young remain near the surface, benefit by some floating plants, particularly Riccia. Angel-fish are a special case; their tank must be full, and should have a large Amazon sword-plant in it, or strips of slate stood upright. They need soft acid water. Sometimes they rear their young successfully, but often it pays to remove the leaf or slate on which the eggs are laid and hatch them in separate receptacles with aeration. Breeding Angel-fish is a tricky business, and not for the beginner.

Hatching And Development

Once the eggs are laid, they should be left to hatch; this will occur more quickly at high temperatures than low, but the offspring will be stronger if developed more slowly, so average temperatures for the species should be used. Sometimes aeration is necessary. The times of hatching may vary from 36 hours to a week.

When the parents are removed, a little infusoria should be put in the tank, and a lettuce leaf floated on the top. Then, if the young develop sooner than expected, there will be food for them.

When first hatched from the egg, the larvae are like splinters of glass, and usually have part of the yolk of the egg included in their bodies for the first few hours; during this period they are not very active. As soon as the yolk has been used up they begin to swim more freely and look for food.

When they are seen to do this, plenty of infusoria should be introduced. Often it is not realized how much these fry can eat. Should infusoria fail, dehydrated egg, dusted lightly on the surface, can be given instead, but is not so good. After a time they will be big enough to eat Brine-shrimp or micro-worms, and then the smaller sizes of Daphnia, and at that stage begin to look more like their parents.
These feeding instructions apply to practically all egg-layers, for even when the parents care for their young they cannot provide food for them. With Livebearers, infusoria are not essential, for as soon as the young begin to swim they can take Brine-shrimp and the finer grades of dried food.

The Water Problem

Failures to breed fishes are often due to using the wrong water, and every aquarist should study this question before embarking on the venture.

If you live in a district where the water is naturally soft, you are fortunate, for you will be able to use the ordinary mains supply without worry. The great majority of aquarium fishes thrive best in soft waters. For Livebearers you will add a little sea-salt—a teaspoonful to the gallon will be plenty.

Hard water has a comparatively large amount of mineral matter, particularly lime-salts, dissolved in it. The most modern method of testing the hardness is known as the Versenate method, in which a sharp color change occurs when the test is complete. A chemical indicator is added to a water sample of definite size, and the number of drops of testing solution needed to change color is counted, and the hardness is indicated on a chart. This is both much faster and more accurate than the older soap test method. (See page 124 for more information on this hardness test kit.)

Where clear rain water is available, no problem exists. The serious hobbyist in hard-water areas should experiment with combinations of distilled water, well aerated, and the local water as it is, or softened and mixed progressively into the aquarium. This is a real challenge and a worth-while objective for the advanced hobbyist in every geographical area, and one which should earn him the sincere thanks of his fellow hobbyists in the community.

As most tropical fish we keep come from waters that are comparatively soft, you can understand that you will have to do something about hardness if you want to keep and breed these species successfully. It must be understood that your fishes probably will survive in harder water than they are accustomed to, but will not thrive so well as in their natural medium.

It is easy to understand this if we realize that an exchange goes on between the liquids inside the tissues of the fish and the surrounding water, and that this exchange depends largely on the amount of salts in the fish and water respectively. Any excess has to be dealt with by the kidney, and the strain on these organs in hard water is likely to be considerable. Moreover, when the eggs are laid, they absorb the surrounding water, and if this is not right it may have a disastrous effect on the embryo.
This movement of solutions through the walls or membranes of animal tissues is known as "osmosis", and we know very little about it except in the way it affects some fishes.

Softening the water with a softening unit may increase the osmotic effect and actually hamper spawning, although here again we do not know enough about it.

On the other hand, the addition of acid materials, such as humic acid (peat moss extract), may combine with free alkaline material and precipitate out of the water as salts and reduce the osmotic pressure.

PH

The above letters are used to indicate the amount of acid or alkaline material that is in the water. Chemists have set up a scale running from 1 to 12, with 7 as a neutral point at which the water is neither acid nor alkaline. As the numbers on the scale go down (from 6 to 1) the water is increasingly acid. As the numbers go up (from 8 to 12) the water is increasingly alkaline. Most waters the hobbyist is concerned with range  from an acid 5 0 to an alkaline 8 5.

When water content is discussed it is not possible to consider only hardness or only pH. The two are inseparable. Each has an effect on the other. For instance, in experiments on adjusting the pH, it was necessary to start with water which was free of any hardness compounds because these compounds would combine with any material we added to lower the pH (or make it more acid).

The use of a water softener is therefore necessary in some areas as a preliminary to reducing the pH.

Eastern United States waters, which are normally soft, frequently become increasingly acid as fish live in them for some time. It is quite common to see calcium blocks or pieces of marble in the aquarium as the acid will unite with the calcium or marble and thereby reduce the acid (raise the pH number closer to 7-0). (If the aquarium water in which the calcium or marble was placed happens to be soft water, it will gradually become harder, as we have cautioned you about in the beginning on page 24.)

Thus you will see that it is difficult to control the pH of water by the addition of acid materials unless the excess free alkalines have been stabilized (changed to inert compounds) by first softening with an ion-exchange softener.

This is no problem for the amateur to become involved in technically, as it would be impossible to cope with the millions of possible water combinations.

Trial and error experimentation is our only suggestion to the hobbyist. The fact that difficult spawnings are being successfully conducted every day gives a lot of hope for success. Patience and a methodical record-keeping approach are necessary.

Healthy eggs are transparent and bubble-like; sometimes they simply fall to the sand, but many kinds are sticky or provided with filaments so that they become attached to the plants or to rocks.

If the eggs become chalky white, or develop a powder-puff-like growth of white fungus, they are dead, possibly unfertilized; there is usually a proportion of such eggs in a batch, and they should be at once removed with a dip-tube, without disturbing the others.

Sometimes the young hatch well enough, but die off when about half an inch long; this is nearly always due to the osmotic effect of the wrong water, which has slowly undermined their health; if the water is too hard their bodies are dehydrated, and if too soft they are waterlogged, for the weaker fluid tends to pass into the stronger.

Culling

Assuming, however, that all is well, the young must be fed regularly and soon will be big enough to be "culled". This means that the obvious weaklings, or "runts", which are much smaller than the others, or bent or otherwise deformed, should be weeded out, and the rest divided into two or more lots. If not, they will overcrowd the tank, and many will be lost. Besides, the more room they are given the faster they will grow.

So that is where we came in. After a time they will be adult and can be bred in the same way.

Spawning Frequency

Cold-water fishes usually breed only once a year, in the spring, but "tropicals" may spawn two or more times. The Livebearers often produce a brood every six weeks or so; they, however, are exceptional, as only one fertilization is needed for several broods—indeed, the female often needs a mate but once, for her life is so short that after her fourth or fifth brood she is too old. Usually the first brood produced by these or any other fish will be the strongest and most numerous, and that is why it is worth-while taking care to make it a success.

Specialization

Most aquarists try to collect as many different kinds of fishes as possible in their tanks, and simply play about at breeding first this and then that. This kind of thing does not get very far.

The hobby today is greatly in need of people who will specialize on a particular type of fish and breed it in quantity and quality. This has been done in Germany for a long time, and the result is that the greater part of aquarium-bred stock is imported from that country. There is no need for this really, for the Germans have no facilities or knowledge that we do not possess—only organization. The amateur breeders cooperate with the dealers to the benefit of themselves and their country. Many working people, with modest incomes, take up aquarium-keeping, and after a time become experts on one particular variety which they can breed almost at will. By selling the surplus to the dealers they cover the expanding cost of their operations. Moreover, the dealers pass to them any novelties which may be related to their speciality, and they reproduce those also.

There are many beautiful and popular species about which very little is known, and specialization on some of these would be well worth while to anyone who cares to begin. Aquarium-bred fishes are always more preferable to wild ones, and the production of good domesticated stock will therefore be a real benefit to the hobby as a whole.

Surplus Fish

If you begin breeding fishes, you cannot possibly accommodate all the progeny, so will have to find ways of disposing of them. The "runts" can be used as fish-food—it is all they are good for. Never pass runts to a beginner, if you wish him well, for it is the most certain way to discourage him. You will be doing a good job for the hobby if you help another aquarist on his way, with the best fish you can spare. For the rest, you can make exchanges with members of your society, or with your dealer. Most dealers need good stocks, but they often get a raw deal from aquarists, who think the trader should take all their throw-outs at good prices; some even set up as part-time dealers in competition, but seldom for long. Aquarium trading is not so profitable as it looks at first sight, and if you take up fish-keeping with the idea of making easy money, I advise you to reconsider it. You will get a fair price from your dealer for good stuff at a sellable size; he will charge more to his customers because he must cover his overheads and also the considerable loss of stock which he has to support. He it is who imports those novelties from abroad which we value so much, and in doing so many die in transit. Go-operation from breeders will help him, help the growth of the hobby, and incidentally help cover the cost which an increasing line of fish-tanks entails.
Many a hobbyist has found success as a hatchery operator, working full time, and employing others, as the hobby grows.

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