Callanthias japonicus has a dorsal fin which is supported by 10 spines and between 11 or 12 soft rays while the anal fin has 3 spines and 10 or 11 soft rays. It has an elongate, compressed body with a short, blunt snout. The preoperculum is rounded and has no spines or serrations but the operculum has 2 spines. The overall colour is pink, shading to yellow on the blower body. This species has a maximum publishedstandard length of.