A new clingfish, Kopuavermiculata, is described on the basis of a single specimen collected from ca. 100 m depth off the Pacific coast of Honshu Island, Japan. The new species is distinguished from its congeners by having the following characters: dorsal fin rays 7; anal fin rays 6; segmented caudal fin rays 15; upper procurrent caudal rays associated with both neural spine of second preural centrum and epural; vertebrae 35; nasal pores 1; lacrymal pores 3; mandibular pores 3; predorsal length about 60 % of standard length; body whitish with distinct reddish-orange blotches on body; no reddish-orange stripes on cheek; belly whitish. A key to the species of Kopua is provided.