A Lancefield group C streptococcal (GCS) infection caused by Streptococcus dysgalactiae that is characterized by severe necrotic lesions of the caudal peduncle has been an increasing cause of mortality in farmed fish such as amberjack, Seriola dumerili , and yellowtail, Seriola quinqueradiata , in the southern part of Kyushu, Japan. In this study, enzymatic profiles of GCS strains from fish and mammals were investigated using...