Fungus Infections in Fish

Fungal diseases are a common issue faced by tropical fish owners. These diseases are particularly problematic because they can rapidly spread and infect other fish. Fortunately, most fungal infections are treatable.

  1. Types

    • According to Doctors Foster and Smith at the Live Aquaria website, there are a number of different fungal infections that affect fish. Cotton wool disease, for example, is caused by the saprolegnia fungus. It infects the mouth, fins and skin with a cottony grayish white growth. Other infections such as ichthyophonus hoferi cause generalized ill health, while the branchiomyces fungus causes the gills to rot away in a condition called gill rot.

    Causes

    • Fungal infections are caused by sick fish that have been introduced to the tank, as well as by dead fish, decomposing plant and animal material, and poor water quality. Doctors Foster and Smith indicate that healthy fish in well-maintained tanks rarely ever suffer from fungal infections.

    Prevention/Solution

    • Treat saprolegnia infections and gill rot with the antifungal medication phenoxyethanol. Use malachite green to treat ichthyophonus hoferi infections. The Pet MD website adds that cleaning out the tank and removing dead fish and organic matter will help prevent the spread of the disease.