: Infected or suspectedfishes were randomly sampled from selected farms and then organs such as brain, kidney, spleen and liver sterile swabs were streaked on brain heart infusion agar plate (BHI) supplemented with 1.5% NaCl. Plates, blood agar and MacConkey agar plates were transferred to the laboratory, where they were kept on ice and incubated at 25°C for 48 h. The bacteria were harvested by centrifugation at 3,500 g, 4°C for 10 min. Suspected bacterial colonies were subcultured onto BHI, blood agar (5% sheep blood) and identified using the conventional biochemical system [18]. Antibiogram tests using the disk diffusion method [19] were performed to determine the antibiotic susceptibility of isolates. Pure cultures were then sampled and subjected to morphologic and cellular fatty acid analysis.