The successful treatment of tropical fish tank granuloma (Mycobacterium marinum) with co-trimoxazole.

Three cases of tropical fish tank granuloma caused by Mycobacterium marinum (balnei) are described. Abundant acid fact bacilli were demonstrated in homogenates prepared from the fish thus providing early confirmation of the suspected clinical diagnosis: acid fast bacilli could not be demonstrated in biopsy material from the patients' lesions through M. marinum grew on culture. The infection responded to oral co-trimoxazole.