Indo-Pacific: throughout the region excluding the Hawaiian, Marquesan and Easter islands. Record from Baker Island (US Minor Islands) based on a photograph.

Body dark olive-brown. Orange spots on head. Pectoral fin yellowish, caudal and ventral fins brown, anterior part of caudal fin pale. Each side of caudal peduncle with sharp, forward-pointing erectile spine which folds down into a horizontal groove. Scales minute. Juveniles with 8 - 12 pale stipes inclining downward and backwards on body.

Inhabits reef flats and lagoon and seaward reefs to a depth of over 30 m. Occurs over coral, rock, pavement, or rubble substrates. May occur singly or in small to very large, often mixed-species aggregations. Feeds on surface film of blue-green algae and diatoms (making this species a key link in the ciguatera food chain) as well as on various small invertebrates.