Total collected 36 Aeromonas isolates from various healthy fishes of different regions in Bangladesh were characterized for their species and serogroup designations. After different morphological and biochemical characterization, it was found that, 25 of them were A. hydrophila. Serological studies were done by performing slide agglutination tests followed by agglutination titration. Agglutination ability of all the isolates (FKC and HKC) with 10-fold and 20-fold dilution of previously prepared anti -A. hydrophila rabbit serum were observed. We found 3 serotypes (serotype, A, B and C) from the tested 25 isolates form. The titers were 640-1280 (FKC) and 160-320 (HKC) for serotype A, 160-320 (FKC) and 80-160 (HKC) for serotype B. For serotype C, the titer was 20 (both FKC and HKC).