Goldfish Fungus

Goldfish fungus is caused by the saprolegnia and achlya organisms, usually as a secondary infection occuring after goldfish illnesses such as ulcers or parasites. Fungus can also infect wounds that are a result of injury. In tanks and ponds with good water quality fungus is rarely a problem.

Fungus appears as a cotton wool-like or fluffy growth on the skin and/or gills, and is gray-white in colour. Sometimes excess mucus is visible around an open sore or the goldfish's gills.

When discovered, it is important to make sure the water quality is high. Treatments are available from pet shops and vets, and quick action usually cures the infection. If treatment is unsuccessful there is a chance it is not fungus, but one of the bacterial goldfish illnesses called cotton wool disease. It has a similar appearance, but obviously will not respond to anti-fungal medication.