Prevalence of microscopic tubercular lesions in freshwater ornamental fish exhibiting clinical signs of non-specific chronic disease.

A histopathological study of tubercular lesions in ornamental freshwater fish showing clinical signs of chronic sporadic disease was carried out using conventional and acid-fast staining. A total of 200 individuals of 38 species were examined for granulomatous lesions related to the occurrence of acid-fast bacteria. Tubercular lesions were found in 24 species. Systematic histopathological examination was used to assess the incidence of fish tuberculosis in aquaria.