Abstract
An epizootic occurred among pond-cultured ayu, Plecoglossus altivelis, in Tokushima Prefecture in 1978. The symptom was characterized by both exophthalmos and subcutaneous hemorrhage.
One species of bacterium was purely isolated from all these diseased fish, and submitted to characterization tests and pathogenicity tests with healthy ayu and eel, Anguilla japonica.
Putting the results together, the etiological agent of the disease was identified as Aeromonas hydrophila subsp. hydrophila. This is the first record of A. hydrophila infection in pond-cultured ayu in Japan.
