Deep compressed body; a small mouth with brush-like teeth; preopercle with large spine at its angle, with vertical margin serrated; bone between preopercle and operculum with 1-4 large spines; bone under eye without large, rear-pointing spines; a single, un- notched dorsal fin, XIV, 18-20; anal rays III,17-19; dorsal and anal fins end in filaments; tail straight; lateral line weakly developed, ends under end of soft dorsal fin; large (~ 50 in lateral series) regularly arranged, very rough scales with distinct ridges on the exposed part, scales extend out onto the median fins.
Velvety blue-grey with blue scale centers; a narrow white bar on side at level of rear edge of pectoral fin; tail fin yellow; juveniles orangish anteriorly, brown posteriorly, 5-6 narrow blue bars on side and pair of similar bars on head surrounding broad brown bar through eye.
Maximum size about 36 cm.
Habitat: juveniles sometimes found in tide pools. Relatively common on rocky reefs or coralline areas.
Depth: 1-80 m.
Central Baja to the Gulf of California to northern Peru, including the Revillagigedos, Galapagos, Malpelo and Cocos.