Elongate, slender, compressed body; 1 pair canines at front of top jaw, 1 pair on bottom, none at rear of jaws; preopercle edge smooth; dorsal fin VIII, 13; anal rays III, 11; pectoral rays 15; tail fin concave; lateral line unbroken, but bends abruptly down near end of soft dorsal fin; scales large (26-27 on lateral line), smooth; head scaleless.
IP: with pair of bright yellow and red stripes bordering broad dark brown to greenish stripe from snout through eye along head and body; TP: body purplish, a broad yellow bar just behind head; tail bluish; head bluish with darker blue-green stripes below eye; pectoral yellow, with blue margin.
Maximum size to 15 cm.
Forms aggregations that feed on plankton around rocky and coral reefs, also feeds on benthic crustaceans, and fish eggs; the young sometimes "clean" parasites from other fishes.
Depth: 0-64 m.
Central Baja and the Central Gulf of California to central Peru, plus all the offshore islands except Clipperton.