US Fish & Wildlife Service


Date of this Version



Published by UNITED STATES DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Division of Fishery Research Washington, D. C. 20240


Mycobacteria are widely distributed in nature. They are abundant in the soil, on the surface of plants, on the skin of vertebrates, in human food (e.g., milk and butter), and in animal feeds. Most mycobacteria are saprophytic, but some species are highly pathogenic and cause diseases such as tuberculosis and leprosy in humans, and similar diseases in mammals, birds, reptiles, amphibians, and fishes.

Mycobacteria that cause diseases of fishes differ considerably from those that cause diseases in humans and other mammals. Therefore, to avoid association between tuberculosis in mammals and mycobacterial infections in fishes, it is better to call the disease "mycobacteriosis of fishes."