Mycobacterium fortuitum Cruz from the tropical fish Hyphessobrycon innesi

Mycobacterium fortuitum, a rapid-growing, acid-fast bacillus, isolated from a cold abscess of human origin was described by Cruz (1938). Gordon and Smith (1955), in a taxonomic study embracing a group of acid-fast bacteria capable of relatively rapid growth on ordinary media, classified a number of cultures in their collection as M. fortuitum Cruz. In this group were strains isolated from human beings, cattle, soil, and cold-blooded animals including marine fishes. The present study was undertaken to determine the identity of a rapid-growing, acid-fast bacillus isolated at the New York Aquarium from lesions present in a population of freshwater tropical fishes commonly known as the Neon Tetra (Hyphessobrycon innesi). The symptomatology and pathology of this disease have been described by Nigrelli (1953).