Water Works Wonders

Large Parasites

Only a few parasites visible to the unaided eye ordinarily attack fishes. These include fish lice (Argulus), leeches, anchor worms (Lernaea), and grub worms (Clinostomum). Most of these parasites will be found on pond fish or aquarium fish recently brought in from ponds. They can also be introduced on plants, pond water or poorly cleaned live food. In nature these parasites are rarely serious causes of illness but in confined quarters they can overpower the fish.

The fish louse is about 1/8 to 1/4 inch long and is an oval, clear, blister-like animal when seen on the side of a fish. The fish’s skin under the parasite will frequently show a blood spot. The lice may occasionally be seen swimming freely in the water. Leeches found in the aquarium may attack fish. They measure an inch or more when mature, but are very flexible and can stretch remarkably.

Anchor worms enter the fish’s body as a microscopic form, and only weeks or months later when they protrude from the skin is the hobbyist aware of their presence. They form a blister on the surface of the skin with the worm protruding from it.

Grub worms are the immature stage of a larger fluke and cannot multiply in the aquarium. They are approximately 1/8 to 1/6 of an inch long. They may protrude from the skin in a blister with a white center.

The treatment of infestations with all of these is similar and simply involves mechanical removal of the parasite. In the case of the fish louse and leeches, the organism can be simply picked off with a tweezers. The point of attachment on the fish can be treated with a drop of mercurochrome to help prevent secondary infection with bacteria or fungus. The anchor worm is fastened very strongly and may be difficult to remove without injuring the fish. The fish can be held in a moist net and a drop of concentrated salt solution should be placed directly on the parasite. Then tweezers can be used and will require considerable tension to remove the worm. A large fish may be injured in this process and smaller fish may be killed. Grub worms may be removed similarly by opening the skin cyst containing the parasite and removing it with a needle or tweezers. Mercurochrome may also be used on the wounds resulting from the anchor worm and grub worm.

Small Parasites

Two flukes are common parasites of aquarium fishes. These are Dactylogyrus (gill flukes) and Gyrodactylus (skin flukes). Both organisms are directly transmitted from one fish to the other and the rate of transmission is partially dependent on crowding. The affected fish will have a shimmying behavior and will be seen scratching themselves against gravel, plants, etc. A strong magnifying glass will show the slender skin flukes on the surface of the fish. Gill flukes usually cannot be seen; at times they may be visible at the edge of the gill cover. The skin and gills will develop increased amounts of mucus with a slimy appearance and may show small blood spots. A formalin dip is effective in treatment of individual fish before they are introduced into the aquarium.

A contaminated tank however cannot be effectively treated with formalin. Certain precautions must be taken. The hobbyist must make sure the sponge has no soap in it. Various brands may have other toxic elements in them and the sponge should preferably be tested on a less expensive fish in an isolated tank. The pH in the tank should be checked with an accurate pH kit and should be maintained at a slightly alkaline level during the treatment (pH 7.2 to 7.4). The treated fish should be observed frequently and about half the water changed if the fish shows signs of distress. Use one standard size copper sponge for a ten-gallon tank. The copper may be removed after the fish’s symptoms disappear. Copper pennies are also effective. Use twenty pennies per gallon of water. Remove them in twenty-four hours. This treatment is also effective against a number of other parasitic organisms and will be mentioned later.

Humans also are subject to superficial skin infections with flukes. Swimmers in the Great Lakes area are familiar with the “Swimmer’s Itch” which is due to a short lived infestation of the skin with larval forms of the fluke which does not normally parasitize human beings. The infection is self limited but annoying. Fish flukes in aquariums do not attack humans.

Ichthyopthirius Multifiliis is the name of a protozoan parasite which is the cause of the most common fish disease, “Ich”. This is a unique infection in that it is usually fatal if untreated, yet is probably the most easily cured of all fish afflictions.

The affected fish appears to be sprinkled with very small white spots on the fins and body. In the early stages of the disease only one or two spots may be seen, but in the later stages the fish may appear to be covered with them. Similar spots are present on the gills but of course are not visible externally. The parasite’s life cycle involves a free swimming stage and the visible encysted stage on the fish. The recommended medications are most effective during the free swimming stage, and an important part of the treatment is to raise the water temperature to speed up the life cycle and move the organism from the protected, encysted stage into the aquarium water where the medications will have their effect. Temperatures of 80 to 85°F should be maintained until all the spots are gone. In fact elevated temperatures in this range are frequently helpful in treating fish diseases in general and should be resorted to even if the cause of the disease is not known.

A number of drugs are effective against this parasite. The old standby is ordinary table salt in a concentration of about one tablespoonful per gallon of water. This is dangerous to catfish, however, and of course, the salt will remain until the water is changed. Quinine is very effective in a concentration of one grain per gallon of water. It is not toxic in this concentration and will gradually deteriorate by itself. Methylene blue has been used effectively in a concentration of three drops of 5 % solution per gallon of water. (5 % is the usual concentration sold in aquarium shops.) This has the disadvantage of staining many aquarium ornaments and gravel as well as having a toxic effect on some aquarium plants. One of the newest and best medications available is malachite green in a concentration of one drop of 0.75 % solution per gallon of water. This concentration is available in aquarium supply stores under various trade names. The dose is important and an overdose may be rapidly toxic. The drug is not safe with small fry. With any of these treatments an activated charcoal filter should not be used in the aquarium until the cure is completed since the charcoal may absorb the desired medication.

An infectious form of human diarrhea is caused by a protozoan organism called Balantidium coli which is remarkably similar to Ichthyophthirius Multifiliis in its appearance. This parasite generally infests pigs and is sometimes transmitted to humans from them.

This disease should not be confused with “Ich” since, to the experienced eye, the appearance is not really similar, although both are common and are caused by protozoa. The name “rust” gives the best idea of the appearance of an infected fish which will show a very fine pale yellowish, granular appearance on the body. Like “Ich” this disease can and does kill but is curable. It tends to have a longer course than “Ich” and may last for weeks. The causative organism is called Oodinium which also has free swimming and parasitic stages like Ichthyophthirius. The malachite green treatment is effective and safe in the proper dosage. The previously described copper treatment is also rapidly effective. The older methylene blue therapy may not be as successful.

Less common protozoan infections-Chilodon, Costia, and Trichodina are additional protozoan parasites which cause a general debility, weakness, and slimy appearance of affected fish. Young fish also may show a shaking and twitching behavior, as if they were attempting to dislodge the parasites. The organisms crawl over the outside of the fish’s body. With a strong magnifying glass, they may be just visible as minute white or clear dots on the fish or in the water. A few are relatively harmless but in confined spaces can multiply to the point where many organisms are present and can weaken and kill the infested fish. The parasites are usually introduced from ponds or on pond fish. They respond to the previously described copper treatment, Quinine, or formalin dip. The author has also recently used malachite green and acriflavine with success.

Myxosporidia and Microsporidia are less common protozoan organisms which occasionally infect fish and cause the appearance of varying size bumps under the fish’s skin. These bumps’ are actually cysts containing vast numbers of organisms and may measure up to one-half mch in diameter. If the cyst ruptures, the parasites are released into the water and can attack other fish. In addition to the obvious cysts the internal organs are also infected. The fish can harbor a low grade infection with a few organisms without apparent difficulty but occasionally the orgamsms Will multiply and cause obvious illness and ultimate death. No effective treatment is known. The suspected fish should be isolated or destroyed.

A number of bacteria are known to infect fish causing conditions such as fin and tail rot, ulcer disease and furunculosis, and gill infections. Among these are Myxobacteria (slime bacteria), and bacteria in the genera Pseudomonas, Aeromonas, and Hemophilus among others. The hobbyist usually finds it difficult to tell these infections apart and cannot isolate and identify the causative organism. The therapy of the infection is similar however so the differences are not too important for practical purposes. Myxobacteria are responsible for an infection in the mouths of fishes which has been misnamed “Mouth fungus” and also cause a condition called Columnaris disease which is due to an infection by a bacterium, Cytophaga columnaris.

The features which most bacterial infections have in common are ulcers (open sores) on the skin, fins and mouth, internal abscesses, and increased mucus on the skin and gills. These skin ulcers are like the top of an iceberg in that they give only a clue to the marked infection inside the body of the fish. Local treatment with ointments or with dyes such as malachite green or Methylene blue in the water is completely useless for curing the infected fish but may help to prevent transmission of the disease. Pop-eye and dropsy can also be caused by advanced bacterial infections.

Considering the number of bacteria which can infect humans, it would be surprising indeed if only these few recognized groups are the sole cause of fish bacterial infections. Other bacteria in the author’s personal experience falling into none of the above described categories can also cause disease. These may be less pathogenic but attack fish in a generally weakened condition. Bacteria such as these are known as opportunists. Aquarium fish will also be adversely affected and weakened by cloudy water which generally contains vast numbers of usually harmless bacteria.

The treatment for bacterial infections requires the use of antibiotics in the aquarium water which will be absorbed by the fish and which will reach the internal areas of infection. The tetracycline antibiotics are generally effective and are sold under various trade names. The forms of the drugs intended for human consumption can sometimes be used in aquarium water. Do not use any oral liquids or suspensions which may contain flavoring and sugar. This may result in giving rise to bacterial infestations in the water worse than the disease being treated. The best form to use is a capsule of pure drug which can be emptied into the aquarium water. Some forms of these drugs will yellow the water and cause the formation of scum and foam on the surface. Penicillin in its usual forms is effective against only a limited number of bacteria. A newer form of Penicillin, Ampicillin, has a much wider range of effectiveness and has been used by the author with considerable success. This drug is non-toxic to fish in high concentrations and is colorless. The recommended dose is 50 mg. per gallon of water for both the Tetracyclines and Ampicillin.

Fungus infections are rare as a primary cause of disease in aquarium fish. The condition occurs usually secondary to injury or an infection with some other organism which has weakened the fish or caused open sores on the body which serve as a portal of entry for the fungus organism. As previously mentioned, “mouth fungus” is actually a Myxobacterial infection.

Saprolegnia is the name of the group of true fungus organisms usually involved in aquarium infections. The infected fish appear to have fuzzy white or gray patches on their body or fins. Humans also may suffer from a variety of fungus organisms causing skin, hair, and fingernail infections. These tend to be chronic, long term diseases and recur easily. None are acquired from fish.

Treatment is generally simple and involves the use of malachite green, acriflavine, or methylene blue in the usual dosage. The fish may also have to be treated for any underlying condition which gave rise to the fungus infection.

There are no such diseases as pop-eye and dropsy. To any hobbyist who has a favorite fish die with its eye popping out of its head, or with its abdomen swollen like a balloon, this may seem like a strange statement. The point is to emphasize that these conditions are only symptoms of an underlying disease. Treating the symptoms without doing anything about the disease is a waste of time and effort.

Pop-eye (exophthalmos) can be caused by a variety of conditions including abscesses (tuberculous and nontuberculous), generalized edema and tumors. In commercial aquariums where highly aerated water under pressure may be added directly to the tanks, bubbles may form on the fish’s body causing a condition known as air embolism but this should not affect home aquariums. In humans, exophthalmos is most often caused by a dysfunction of the thyroid gland but can also be caused by a tumor or infection.

Dropsy (generalized edema) in humans can be due to chronic heart failure, severe kidney disease, or chronic liver disease. In fish similar causes are found but heart disease has not been recognized in aquarium fish. Tuberculous and nontuberculous infections in the fish’s kidney and liver are the most common causes of the condition. One platy seen by the author had a marked fibrosis and thickening of its body muscle which mimicked dropsy in external appearance.

The treatment of both of these symptoms depends on the underlying disease which usually. cannot be diagnosed without destroying the fish and studymg the organs. Without this diagnosis a rational approach is to isolate the affected fish and treat it with antibiotics. Unfortunately, m order for pop-eye or dropsy to occur, any causative infection must be present in an advanced stage, and cures are rare. The infections usually causing pop-eye and dropsy have an indolant course-rapid infections will usually kill without causmg such symptoms. Occasionally dropsy may recede spontaneously but it will recur and ultimately kill the fish. Pop-eye usually does not recede.

The hobbyist should realize that bactenal infections in fish will sometimes heal spontaneously. Old fish have been found showing healed abscesses in their body although they had never been treated for any illness nor ever thought to have been sick.

Tumors are generally an unimportant cause of disease and death in aquarium fishes, but tumors have been found in almost every organ of many species of fish. Hobbyists specializing in Xiphophorin fishes (swordtails and platys) may be more familiar with this entity. Hybrids of these fishes with black areas on their bodies frequently develop a type of tumor called a malignant melanoma. These hybrids in some cases have deen deliberately developed so that such fish can be used for research in the field of cancer. Humans can also develop a similar tumor on the skin. In their way, fish contribute to our understanding of human diseases. Unfortunately no satisfactory treatment is known. They are not contagious so it is not necessary to isolate such fish unless they are weakened to the point where other fish may attack, them.

Another type of skin tumor in fish can be caused by a virus called Lymphocystis. This also is not too common among aquarium fishes.

A certain number of deformed fry will be found in every large hatch of aquarium fish, especially in highly inbred fish like fancy goldfish. Some of these defects are severe enough to prevent the normal development of the fry, so these seriously deformed fish will eliminate themselves. Less severely affected fish may show various deformities such as crooked backs, deformed mouths and occasional missing fins. The hobbyist should examine his breeding fish carefully to avoid such defects in an attempt to lessen the chances of passing them on to the fry.

Heavy, shortbodied, fancy goldfish seem particularly susceptible to a swim bladder disorder which may be congenitally determined and related to the shape of the body. Tropical fish occasionally may develop the same symptoms. These fish tend to lose their balance and turn upside down as they float towards the surface. No permanently effective treatment is known. Other more subtle defects may be found in fancy goldfish, the most common one being a single anal fin in a double-tailed goldfish. This is a technical defect which, however, is enough to disqualify the fish in a show. Such a fish may be very beautiful but should not be used for breeding, if another choice is available.

The problem of deficiency diseases actually centers on the type of diet available for the fish. Most hobbyists depend to a great extent on dried prepared fish foods, which usually contain an adequate variety of substances of both vegetable and animal origin. Most important is the amount of protein in the food. This can range from 10 % in the poorer quality foods to over 40 % in the better quality foods.

Golden dried shrimp is a good supplement to the commercial dried foods. The best preparation to use is not that sold as fish food which usually contains quantities of inedible shell and husks, but that which is sold for human consumption. This is not much more expensive and is a far better food.

Regardless of the quality of dried food used, the fish will do better and grow faster if they are also frequently fed live or frozen food. This is especially important for young fish to help them to reach their greatest growth potential.

Foods available include tubifex worms, live daphnia, and live brine shrimp. These are also available in frozen form and in the author’s experience seem to be as good. Care should be taken when using live tubifex and daphnia to see that no parasites are introduced into the aquarium with the food, which should be carefully washed and examined. The author currently uses frozen brine shrimp instead of the previously preferred but more expensive live tubifex, but has noticed no significant difference in the disease rate in his tanks. Larger fish may be offered whole or chopped earthworms and meal worms. Both of these can be raised by the hobbyist. Meal worms are clean and can be raised in the home with no mess or smell. Earthworms require more care, space, and are dirtier.

Aside from growth retardation, the most common result of improper feeding is general weakness and poor condition of the fish leaving the way open for opportunists, parasites and bacteria which ordinarily may be harmless, to attack the weakened fish.

The only actual deficiency disease found by the author resembling that in humans was a Lion fish Pterois volitans at a large commercial aquarium. The fish had symptoms of loss of balance and tumbling, not floating as in a swim bladder disorder. Studies of the brain of one of these fish revealed degenerate changes like those found in severe vitamin B deficiencies in humans. These adult fish had been fed only one type of frozen food since their capture as small fish. When their diet was changed and varied the fish improved remarkably and returned to normal behavior.