Seasonal variations of bacteria in surrounding environment and Etroplus suratensis were studied. Maximum bacterial counts was recorded during (Feb-May, 2009) in water and sediment samples ( 2.78 x 106 CFU.g-1). Bacterial counts associated with fishes was recorded in healthy and diseased fishes (6.15 x 104 CFU. g-1 ) in station II (Buckingam Channel) and Bacillus sp and Micrococcus sp were predominant in gills and skin in healthy fish and Vibrio sp. were predominant in gills and skin in diseased fish. This comprehensive study could provide an information to findout the etiology of fish health to improve the quality and quantity of the fish for human consumption.