In this paper 253 species of fishes are recorded from Oosima-gun, Yamaguti Prefecture. They include freshwater fishes in Yasiro River and bottom fishes obtained by small trawlers in Iyonada. The majority of fishes found in the region are those of temperate forms with some admixture of subtropical forms. The following rare fishes are secured in this region. 1. Trashipterus nigrifrons SMITH(Fig. 1) One specimen, 450mm, Agenosho, Oosima-gun. D.191