Diseases in the Aquarium - Part II
A nearly complete guide to Fish Diseases

An Article by George J. Reclos

Costiasis  (see Sliminess of the Skin)
Dactylogyrus (see Flukes

DISEASE Actually it is a pest (the larval stages of some dragonflies).
SYMPTOMS The larvae of some dragonflies may prey on fish and fish fry in fresh water.
TREATMENT This infestation is rather infrequent in aquariums. Should a problem occur the only real answer id to refurbish the whole tank and thoroughly clean all elements.

DISEASE ODEMA or DROPSY - causal pathogen(s) not certain - possibly multiple fungal/bacterial or viral infection. It could be due to a metabolic or nutritional disorder.
SYMPTOMS Fish's body bloats out (as though full of roe) and, viewed from above, scales stand away from body producing a pineapple-like appearance - most common in Carp family and Anabantids. Long, pale faecal casts. Ulcers on body, pale gills and a "pop eye" appearance are also common.
TREATMENT As soon as abdominal swelling is noted isolate the fish and treat with a broad spectrum antibiotic. Early treatment is essential. You could use oxytetracycline (20-100 mg/ litre; five days bath, may need repeating), tetracycline hydrochloride (40-100 mg/ litre; five days bath, may need repeating)or minocycline hydrochloride. For minocycline we recommend 250mg/10 gallons of water. On day 2 change all the water and add the medicine again at the same dose for another 2 days. Increase aeration during treatment. Do not use minocycline a third time in a raw. Caution: tetracyclines are photo sensitive - turn lights off during treatment - better still cover the whole tank with a blanket. If the fish is still eating, soak the food in a concentrated solution of the antibiotic before feeding.
PREVENTION Avoid overfeeding or feeding the wrong kind of food (e.g. vegetable matters to carnivores).

Ergasilus - gill worms (see Gill maggots)
Eye cloud
DISEASE A symptom common to many diseases (eye fungus, worm cataract Proalaria) and water condition problems. If eyes are protruding this may be an indication of more underlying diseases.

Eye fluke
DISEASE Caused by the larval stage of digenetic fluke parasites, such as Clinostomum, Posthodiplostomum and Dipplostomum.
SYMPTOMS The parasite responsible lodges in the lens, humour (liquid) or retina of the eye and may do considerable damage if present in large numbers. The extent of this damage ranges from eye cloudiness to lens rupture and blindness. Low-level infestations may occur unnoticed. TREATMENT Very rarely necessary and is difficult if not impossible. Copper treatment (continuous bath) may help. Organophosphorous antiparasitic remedies may be used too.
PREVENTION Avoid obviously infected fish and discourage fish-eating birds from visiting garden ponds to prevent the life cycle being completed.

Fin and tail rot (bacterial)
DISEASE Usually caused by various bacteria such as Aeromonas, Pseudomonas and myxobacteria.
SYMPTOMS Split, ragged or stumpy fins, often with a white edge to them.
TREATMENT Chlortetracycline 10-20 mg / litre, continous bath for up to 5 days, may need repeating. Oxytetracycline hydrochloride 20-100 mg / litre, continous bath for up to 5 days, may need repeating. Caution: tetracyclines are photo sensitive - turn lights off during treatment - better still cover the whole tank with a blanket. If the fish is still eating, soak the food in a concentrated solution of the antibiotic before feeding.
Nifurpirinol up to 2 mg / litre may need repeating. 5-10 minute bath.
Other commercially available medications designated for aquarium use. Follow instructions. In all cases it is better to overdose than to underdose.
PREVENTION Some of these pathogens can be transferred in tank by the keeper. Wash your hands before putting them in the tank water.

Fin and tail rot (fungus)
DISEASE Caused by various species of aquatic fungi, including Saprolegnia and Achlya
SYMPTOMS Gray, brown or white cotton-wool-like growths or tufts on the skin and fish of freshwater and brackish fish. Begins as a small patch but can develop and quickly kill the fish.
TREATMENT Use a proprietary fungus remedy. Treat the whole tank but isolate and treat heavily infected fish separately. Methylene blue can also be used; 2 mg/litre, continuous bath for several days - repeat if needed.
PREVENTION Find and eradicate causal factor. This disease occurs in fish with poor health. The spores or seeds that give rise to the fungal infection are very common to water but can only penetrate the skin of fishes that have been damaged either by fighting, spawning activity, or attack by other parasites. Not correct water parameters, stress, poor hygiene or physical damage usually encourage the onset of the disease.

Fish pox
DISEASE Fish pox, a viral infection.
SYMPTOMS White, gray or pink growths appear on the skin and fins. In many cases, an affected fish looks as if molten wax was poured over the body. In extreme cases the growths may become too pronounced and bear similar pigmentation to the surrounding skin.
TREATMENT There is no reliable treatment. Raising the temperature by 2-3 degrees may eliminate the problem temporarily. Since even badly affected fish do not seem to suffer and the infection is not markedly infectious you shouldn't be too concerned. It is unsightly rather than dangerous.
PREVENTION Avoid buying infected fish.

Fish tuberculosis (see Wasting Disease)

DISEASE Caused by free living animals.
SYMPTOMS Such animals appear to suddenly "bloom" in an aquarium. Small flatworms, which can be white, cream, red or orange in color, usually move with a smooth gliding motion. They are usually a few millimeters to, perhaps, a centimeter in length.
TREATMENT None effective but prevention is effective.
PREVENTION Do not overfeed, regularly maintain the filter and clean the gravel often.

DISEASE FLUKES - external and internal "worm" parasites belonging to the classes Trematoda and Cestoda species in the family Dactylogyridae parasitise the gills and digestive tract. The family Gyrodactylidae parasitise the body and finnage. Cestodes parasitise the internal digestive tract.
SYMPTOMS In early stages (first 24 / 48 hours) fishes show signs of extreme skin/gill irritability, continually scratching and scraping on rocks etc., and "flicking" the pelvic and dorsal fins against the side of the body. However, unlike diseases which can share the same symptoms of skin irritation sometimes, this condition never causes an increase in breathing rate until the fish, after several days / weeks without treatment, is approaching death, and rarely are the near microscopic parasites noticeable as spots on the body, although they can sometimes be seen as blurred spots on fins.
TREATMENT Carry out partial water change and treat the tank with formalin. Stop all feeding till symptoms disappear and "spring clean" filter bed. Bear in mind that these diseases are extremely contagious.
PREVENTION Maintain a much higher standard of aquasystem hygiene, paying particular attention to filter cleanliness and avoiding overfeeding. Always stir up filter-bed before siphoning off old aquarium water when carrying out a partial water changes. Never use non-irradiated seafoods, Daphnia, Tubifex, bloodworm, mosquito etc. Above all - carry out routine prophylaxis at least once per month on all systems.

Fungus (see Fin and Tail rot - fungus)

Furunculosis - aeromonas (see Haemorrhagic Septicaemia)

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