Abstract
A survey of the occurrence of mycobacteria was conducted from 717 freshwater fish (25 species) in two water reservoirs, five ponds and two farms in the Czech Republic. A total of 2182 tissue samples from these fish were examined using the conventional culture method. Thirteen mycobacterial isolates were obtained from 12 (1.7%) fish belonging to nine species. Isolates were identified using sequence analysis of the 16S rRNA gene as: Mycobacterium algericum , M. fortuitum , M. gordonae , M. insubricum , M. kumamotonense , M. nonchromogenicum , two isolates of M. peregrinum , M. terrae and M. triplex . Mycobacteria were isolated more frequently from fish skin and gills than from internal organs or muscles.