Ailments And Enemies

Some textbooks on aquarium-keeping devote a considerable space to the subject of this chapter. In the present work it will not take very long, because if you follow the earlier instructions faithfully you should not be bothered very much with diseases and parasites. And I have left it until the end because it is the last thing you should think about. Aquarists who fear that their fish are sick, or worry about every little blemish, have the most trouble, because they are continually juggling with salt-baths, temperatures and a host of drugs.

Still, trouble comes to the best of us, and there are some things that you must know about, even though they ought never to happen.

Chill

If you have been careless about temperatures when transferring fishes, or topping-up the tank, fishes may suffer from chill. This shows itself as loss of balance due to the swim-bladder being affected, a wagging of the body from side to side as though trying to swim fast but getting nowhere, unnatural redness about the gills, paling of the colors, gasping near the surface or skulking in a corner, and loss of appetite. Some or all of these symptoms may be present. Treatment—raise the temperature. If only one or two fishes are affected, take them from the tank and put them in a smaller receptacle, raising the temperature in that to 85 ° or 9O°F. If no improvement is noted after 24 hours, give a salt treatment as follows: add two level teaspoonsful of sea-salt to each gallon of water. Increase this by half a teaspoonful every four hours, until signs of improvement are shown. The concentration should not exceed six teaspoonsful to the gallon, however. If no improvement is shown after three days there is little hope of recovery. It usually works, however, and the salt should then be gradually reduced by taking out part of the water and replacing it with fresh at the same temperature. When close to normal, the fish can be returned to the tank. This laborious treatment is only necessary in severe cases, where there is gill congestion, resembling our bronchitis or pneumonia. In ordinary cases raising the temperature is enough.

Constipation

Due to wrong feeding (too much dried food, or starchy food for instance), this manifests itself by a swollen look about the abdomen, loss of balance, gasping at the surface and loss of appetite. The first sign of it, however, is given by the excrement, which remains hanging in a long string from the vent; if the diet is changed at this stage, trouble will usually be averted. Advanced cases must be treated with Epsom salts—two teaspoonsful per gallon in a small receptacle in which the fish is placed for five to ten minutes; repeat as necessary. Make sure temperatures are equal.

Dropsy

A swollen body and the scales standing out from the skin are symptoms of several disorders, organic, bacterial or parasitic. Salt treatment as described for chill often helps, and in some cases very thick green water is said to do the trick.

Frayed Fins

Splitting or fraying of fins may be due to the attacks of some other fish; if attacked by fungus they should be treated as prescribed under that head, but if not they will heal up. Remove the cause of the trouble.

Another cause may be bacterial infection (known as tail-rot), and the affected part should be cut out with fine scissors and painted with acriflavine while the fish is held in the net. Streaks of blood in the fins are associated with chill or general debility.

Fungus

Injury of the skin of a fish often provides a foothold for white fungus (Saprolegnia), the microscopic spores of which are common in most water. Once it gets a hold it can make the wound worse and even kill the fish. It is visible externally as a cottony white patch. The salt treatment recommended for chill will kill it, or the affected place can be painted (the fish held in the net) with a weak solution of iodine.

Another fungus sometimes affects the mouth after it has been injured, and tends to eat away jaws and gills; it will kill all affected fish unless treated. Aureomycin, 50 milligrams to each gallon of water, should be put in an affected aquarium, But this is expensive, and if the fish are not valuable it may be cheaper to kill them and start again.

Gill-Flukes (Gyrodactylus)

Small parasites that cause the fish to dash wildly about and scrape itself violently against rocks. Fish should be placed in a small clean receptacle, with 20 drops of formalin (40 per cent formaldehyde) to a gallon of water. After 5 or 10 minutes it will appear exhausted and should be removed. Repeat as necessary.

Green Water

This is not, in itself, a trouble. The greenness is due to vast numbers of unicellular algae living in it, and these are more beneficial than harmful while they remain active. When they get thick, however, they impair visibility, and if allowed to go on multiplying over-population will cause the death of many of them; their decomposition may then start trouble. The remedy often advocated for their elimination, namely, to reduce the amount of light on the aquarium, also causes them to die off, with dangerous results. A large mass of decaying matter gives rise to a host of bacteria which produce poisonous substances as a result of their life-processes.

The real answer to green water is to change part of it for fresh, and then increase the number of higher plants in the tank; for it has been made clear before that algae can only thrive if there is an excess of nourishment and light beyond the requirements of the higher plants. After the greenness has disappeared the light can be reduced a little, for too much illumination was probably the start of the trouble. Experience will soon show you how to get the right balance.

Loss Of Appetite

Usually one of the symptoms of sickness. A fish that eats well has little wrong with it. But sometimes even a healthy specimen gets surfeited, or jaded with one kind of food, so try a change of diet before getting worried.

Loss Of Balance

Due to disorder of the swim-bladder or sometimes the inner ear, associated with chill, constipation or intestinal infection.

Metal Poisoning

As mentioned earlier, some metals are poisonous to fishes. Principal among these are copper and zinc, and the alloy composed of them—brass. On no account must these metals be brought into contact with the water. Recent research also names aluminium, chromium, gold, lead, mercury, nickel and silver as dangerous to fish. In practice, it is advisable to prevent any metals at all from coming in contact with the water for any length of time.

Milky Water

This is a dangerous condition, which you should never have if you use the biological filtration method. However, if you do not have a sub-sand filter, the best thing to do is tear your tank down completely, wash the tank and gravel thoroughly and set up again with fresh water. You must do this promptly or you are in danger of losing all your fish.

Pop-Eye (Exophthalmia)

The eye is swollen and bulging, bubble-like. This is due to the accumulation of gases in the eyeball, and is often associated with constitutional ailments. The fish should be netted, held in the wet net, and the eye treated with a mixture of argyrol and glycerine in equal proportions, applied with a swab of cotton or a camel-hair brush. The fish can be kept out of water for three or four minutes to allow penetration before releasing. Repeat as necessary. Cataract (a white film creeping over the eye) and damaged eyes can be treated in this way, but may not avert eventual blindness.

Skin Infection

Appearing as patches of gray slime on the body, can be treated successfully with Protosil or a similar proteid silver compound. This is in powder form, and a five per cent solution in water is made up first, and one ounce to the gallon placed in the receptacle in which the fish is to be treated. The immersion of the fish lasts from two to five minutes, according to its reactions. Repeat the treatment each day for three days. If no improvement is apparent, double the amount of the solution in the water, and continue the treatment. In? fections of this kind are usually due to single-celled parasites, such as Costia, Chilodon or Cyclochaeta. Protosil kills them. A salt treatment, like that recommended for chill, causes them to leave the fish, but does not destroy them. The fish can be returned to the aquarium between treatments, because the little solution which washes them off can only do good.

Spawn-Binding

Females are sometimes unable to deposit their eggs. They become very swollen, tend to lose their balance, and will not eat. Often gentle pressure and stroking towards the vent, while held in the net under water, will help them, and raising the temperature is also beneficial. It is often associated with constipation (q.v.).

Tumors

Hard swellings appearing at any part of the fish, often appearing bloodshot, the skin fraying, are incurable. Kill the fish by throwing it violently against a hard floor or wall—the most humane method.

Velvet

Light brown patches of velvety texture appearing on the back and elsewhere in tropical fishes are due to a single-celled parasite (Oodinium). Dissolve a half-grain tablet of acriflavine in eight ounces of water, and add one teaspoonful of the solution per gallon to the aquarium water. Repeat after a week.

Wasting

Fishes which look emaciated, become concave in the abdominal region, and bent-backed, may be old. Most small tropicals do not live very long—Livebearers two or three years, Gharacins and Barbs about six. If the temperature is kept uniformly high with a thermostat, they may age before their time.

But the appearance may be due to malnutrition, and a change of diet will often correct the trouble. Sometimes it is deficiency of vitamins; Bemax, or a B-complex tablet dissolved in the water, and cod-liver oil added to the food, will often help. Or it may be due to internal parasites, which are difficult to deal with. More often it is the result of overcrowding, and these weak ones should be disposed of.

White-Spot1 (Ichthyophthirius)

This is a common parasitic infection, which appears after there has been a rapid drop in temperature (i.e. when the fish has been slightly chilled). At this time the condition of the mucus (slime) allows the parasite to get a hold, if it is already in the tank. It then appears as white embossed spots, about pin-head size, on any part of the body and fins. If not dealt with, the parasite will reproduce, and the whole stock will be attacked.

Treatment is simple—raise the temperature to 9O°F. and keep it there for a week. It can be lowered to 75°F. during the night to give the fish rest. The parasite cannot reproduce at high temperatures, and as its life-cycle is only four days, it dies out. For cold-water fishes, quinine sulphate, three grains per gallon of water, should be added to the aquarium (dissolve it in a cupful of water before putting it in). Add a little more each day until the spots disappear.
1 See page 115 for information on curing white-spot or "ick".

Once departed, white-spot will not appear again in an aquarium unless re-introduced with new fishes or plants.

Wounds

Fishes sometimes get injured on sharp rocks, in handling or in fights with others. Small wounds can usually be left alone to heal, but if more serious, the fish should be held in a wet net and the injury painted with acriflavine or weak iodine, with a camel-hair brush.

The following measures may be helpful when treating fish:

4 teaspoonfull = 2 dessertspoonsful = tablespoonfull = 1/2 ounce
1.6 ounces per gallon = 1 per cent solution (approx)
8   ounces per gallon = 5 per cent solution (approx)
16 ounces per gallon = 10 per cent solution (approx)
1 ounce = 28.35 grammes = 437.5 grains
1 grain = 0.065 gramme
1pint = 20fluid ounces

Other Nuisances

The introduction of plants from outside waters without sterilization, and live food such as Daphnia without inspection, may result in the appearance of various unwelcome guests in the tank. Some of them will pass unnoticed until they have multiplied, and may then be difficult to eliminate.

Cypris is a small crustacean (up to a quarter of an inch in length) with very hard kidney-shaped shells; in a community tank they do no harm, but act as scavengers. They litter the surface with moulted skins. In a breeding tank, however, they destroy the eggs. Some Cichlids will eat them, but otherwise the fishes must be removed from the tank and the temperature raised to 100°F. for a week or so, to kill them off (Fig. 20, b).

Fish-lice (Argulus), have a flattened, disk-shaped body, about one-eighth inch across, and grip the skin of the fish with hooked feet. They should be removed with forceps while the fish is held in the net, and the place dabbed with a spot of acriflavine (Fig. 20, A).  -

Hydra. These little animals, with a thread-like body up to an inch long, crowned with eight or more delicate tentacles round a central mouth, are dangerous to the fry of fishes; they reproduce by "buds" which break off as small individuals and form colonies on the glass or plants. They contract to a small knob when alarmed. Some Gouramis will eat them, and this is the least troublesome way of getting rid of them.

FIG. 20

A) Argulus; B) Cypris; c) Hydra; D) Planaria

The other way is to take out the fishes, raise the temperature to 9O°F., dissolve half an ounce of ammonium sulphate in water and introduce it into the tank. No Hydra will be alive after three days. The aquarium water must then be changed (Fig. 20, c).

Leeches are rather slug-like worms that may attach themselves by suction to the skin of fishes, and feed on them. They should be removed with forceps, holding the fish in the net, and the wound dabbed with a spot of acriflavine. When seen crawling in the tank they should be removed by hand.

Planaria are small transparent worms of characteristic shape (Fig. 20, D) that may be seen gliding on the glass. There are several species, varying in size from a sixteenth to a quarter of an inch. The larger ones are dangerous to fish eggs and fry. They can be eliminated with ammonium sulphate as described for Hydra.