Sebastes pachycephalus is a species of marine ray-finned fish belonging to the subfamily Sebastinae, the rockfishes, part of the family Scorpaenidae. It is found in shallow rocky reefs of Northwest Pacific. Sebastes pachycephalus has a relatively deep lateral compressed body with a large slight oblique terminal mouth. The head armed with strong preocular, supraocular, postocular, and parietal spines. The space between the eyes is concave. The lower jaw is shorter than the upper jaw and lacks scales. The spiny part of the dorsal fin is clothed in a dense covering of small scales. The dorsal fin has 13 spines and 13 to 16 soft rays while the anal fin has 3 spines and 6 soft rays. The caudal fin is weaklyconvex and almost truncate. This species attains a maximum total length of 42 cm (17 in) and a maximum published weight of 1.6 kg (3.5 lb). The overall colour of the body is brown or dark brown occasionally with a paler brown band or light patterning on the body. There are three light brown bands on the head which radiate from the eye. There may be clear brown spotting on the dorsal, pectoral, anal and caudal fins, although in some fish these may be indistinct. Sebastes pachycephalus Is found in the northwestern Pacific Ocean where it occurs around Japan and Korea as well as in the Yellow Sea and Bohai Sea off China and off the Russian Sea of Japan coast. This is a demersal fish which is found on shallow rocky reefs.
