Study on Isolation and Identification of Bacteria from Infected Fish (Channa Striata)

The current research was aimed at isolation and characterization of disease-causing bacteria from infected Channa striata (Murrel). Infected fish specimens with visible symptoms like haemorrhagic lesions, fin erosion, and abdominal distension were retrieved from aquaculture fishponds. Routine bacteriological techniques were employed, namely, isolation on nutrient and selective agar medium, Gram staining, and biochemical characterization for bacterial identification. The Gram staining test indicated the occurrence of both Gram-positive and Gram-negative bacteria, suggesting polymicrobial infection. Most isolated bacterial genera of frequent occurrence were Bacillus, Streptococcus, Aeromonas, Pseudomonas, and Vibrio, which are recognized fish pathogens that induce septicemia, gill rot, and ulcerative lesions in freshwater fishes. The results demonstrate the importance of systematic bacterial isolation and identification in disease aetiology research. Such research is valuable for the preparation of preventive health protocols, proper diagnosis, and treatment regimens to reduce economic loss in Murrel culture.