In this study, we carried out the rapid diagnostic system based on indirect fluorescent anti-body technique (IFAT) for detection of bacterial diseases in cultured freshwater fishes. 1. When the fishes were tested with graded dilution of Edwardsiella tarda FPC 470 bacteria detection from ten fishes Injected with $4.1{ imes}10^3$colony forming unit(CFU) /ml, all of them were detected by IFAT but only two fishes were recognizable by the culture method in the tested fishes injected with $4.1{ imes}10^3$CFU /ml. 2. The bacteria E. tarda could be detected by IFAT method from 1 to 48hrs after Injection in the tissues tested such as kidney, liver and spleen of the fishes, whereas detection by culture method could be recognized from 1 to 48hrs after injection In the kidney and spleen but it was not possible from preinjection to 1 hr in the liver. 3. Thus, IFAT proved to be more useful technique than plate culture method in the diagnosis of Edwardsiellosis in the freshwater fishes.