Some Bacterial Diseases of Freshwater Fishes in Japan

Edwardsiella tarda (Paracolobactrum anguillimortiferum) and Pseudomonas anguilliseptica are important pathogens of pond-cultured eels in Japan. Recent investigations on their taxonomy, modes of pathogenesis, and sources are reviewed. Pesudomonas chlororaphis was recently isolated from diseased fry of Amago trout, and this bacterium was proved to be pathogenic to fish. “Branchionephritis” is a malignant coldwater disease of pond-cultured eels. Its causative agent is still unknown, though flexibacteria are occasionally isolated from the gills of diseased eels.