Common disease of fish
Causes , Symptoms, Reasons, Actions, Treatments |
Disease and
Causes |
Symptoms |
Reason for
Infection |
Action |
Treatment |
Ulcers
Caused byPseudomonasand Aeromonasbacteria |
Pinky-white open wounds,
often with a white edge and sometimes secondarily infected by fungi and
other bacteria. |
Very poor water quality or an
excessively high pH level. Minor scratches can become infected if conditions
are poor. Also commonly affects newly imported Koi and goldfish. |
Test the water for signs of
ammonia and nitrite. Conduct a large water change to reduce pollution
levels. |
Fish lose salts quickly
through open wounds, so add aquarium salt at a dose of 1-3g/litre. Use an
anti-ulcer treatment. If treatment fails, a vet can prescribe stronger
antibiotics. |
Cloudy eye
Caused by poor water quality, poor diet, eye flukes, corneal
damage, bacterial infection. |
Entire surface or lens of eye
takes on a cloudy, opaque appearance. There may be a build-up of mucus on
the outer surface. |
Most commonly caused by poor
water conditions. A lack of vitamins in the diet may also cause clouding. On
rare occasions digenetic flukes, such asDiplostomum, can cause
problems. |
Improve water conditions. Use
a good quality food containing added vitamins. |
Improving water conditions
usually cures cloudy eyes. Eye flukes are uncommon and can be difficult to
accurately diagnose and treat. |
Dropsy
Usually caused by bacterial infection. Viral infection,
nutritional, metabolic and osmoregulatory problems can also be responsible. |
Swelling of the body cavity
due to a build-up of fluid. Scales become raised giving a pinecone-like
appearance. One or both of the eyes may be protruded. |
Usually triggered by poor
water quality, especially the presence of ammonia and nitrite. Often
confined to individual fish. |
Test water and improve water
conditions immediately. Aquarium salt at a dose of 1- 3g/litre can help to
prevent salt loss. |
Can be difficult to treat. A
broad spectrum anti- bacteria treatment is the best option in most cases. |
White spot
Caused byIchthyophthirius multifiliisparasite |
Small white spots, about the
size of a salt grain, on the skin, fins and gills. |
Stress related. Usually a
consequence of poor or incorrect water conditions, fluctuating temperature
and general poor husbandry. Sensitive species may develop white spot as a
result of being introduced to a new aquarium. |
Ensure the water is free of
pollution and isolate cause of stress. |
Treat promptly with an
anti-parasite medication. It may be necessary to raise the water temperature
to improve the effectiveness of the treatment. Wounds left by parasites may
become secondarily infected. |
Bacterial infection
Caused byAeromonas andPseudomonasbacteria |
Reddening of the skin or fins; ragged fins with
signs of infection, open sores. Common on many newly imported fishes. Often
accompanied by other diseases, including fungi. |
Poor water conditions,
especially the presence of ammonia and nitrite. Wounds resulting from poor
handling, transport or fighting may become secondarily infected by these
bacteria if conditions are poor. |
Improve water conditions, and
treat promptly. |
Use a proprietary treatment
as soon as possible. Aquarium salt at a dose of 1- 3g/litre can help prevent
salt loss. Severe infections may require prescription medications from a
vet. |
Fungus
Caused bySaprolegniaand Achlya |
Fluffy growths affecting
wounds on the skin and fins of freshwater fishes. |
Usually a secondary infection
that invades wounds left by ulcers and parasites, including whitespot.
Rarely a problem in tanks with good water quality. |
Improve water conditions and
treat promptly. |
Standard anti- fungal
medications, such as methylene blue, are usually very effective, but may
affect filtration and water quality. When the disease occurs on open wounds,
aquarium salt at a dose of 1-3g/litre can help reduce salt loss. Cotton-wool
disease (Flexibacter) looks similar but is caused by bacteria and
may require a different treatment. |
Finrot
Caused byAeromonas,Pseudomonasor Flexibacterbacteria |
Frayed fins, often with a
pale pinky-white edge and some blood in the fin tissue. |
The bacteria are present on
most fish. Stress from poor water conditions usually triggers an infection.
Nipped fins may become secondarily infected if water is polluted. Some
wounds may also be attacked by fungus. |
Improve water conditions.
Isolate nippy fishes. |
Treat promptly with a finrot
or anti-bacteria treatment to prevent the further spread of the disease.
Consider adding salt (1-3g/litre) to reduce the loss of salt by the fish.
Ensure that water stays free of pollution during treatment. |
Swimbladder disorder
Caused by bacterial infection, incorrect diet, trapped gas,
physical deformities. |
Fish have difficulty swimming
to the surface, or to the lower levels of the tank. Commonly affects
egg-shaped fancy goldfish. |
Sometimes caused by poor
water quality. Genetic problems in selectively-bred goldfish. |
Improve water conditions.
Feed less dried foods, or pre-soak pellets and flakes so they don't swell
the gut. FeedDaphnia, which acts as a laxative. |
Change diet and improve water
conditions. Treat with a specialist anti-bacteria treatment. Fancy goldfish
suffering from physical deformities will not recover. |
Lymphocystis
Caused by an iridovirus |
The virus causes crusty
grey-white lumps to develop on the skin and fins. These may affect
freshwater or marine fishes, and sometimes take on the colour of the
underlying skin. These lumps are clusters of enlarged cells. |
The disease is viral, but may
be triggered by stress, poor handling or poor water. Some fish may carry the
virus without showing symptoms. |
The disease rarely kills,
although lesions may become secondarily infected. Ideally, infected fish
should be isolated. |
There is no known treatment.
Some vets recommend the surgical removal of the lesions. |