Pacific Ocean: Honshu, Japan south to the Great Barrier Reef and New Caledonia and east to the Hawaiian Islands, French Polynesia, and Pitcairn. Eastern Pacific: Clipperton Island. Once regarded a wide-ranging Indo-Pacific species, the Indian Ocean population is now recognized as a separate species, Naso elegans.

Dorsal fin black, the black continuing as a pointed projection onto nape, with a pale blue line at base and a broad outer white zone on soft portion; anal fin mainly orange; dorsal and anal fins with a narrow blue margin and black submarginal line; caudal fin with a yellow submarginal band posteriorly. Caudal fin emarginate with adult males having trailing filaments from each corner.

Found in areas of coral, rock, or rubble of lagoon and seaward reefs. Benthopelagic. Adults usually in small groups. Juveniles in shallow rocky reefs, sometimes in small aggregations mixed with other acanthurids of similar size. Feed mainly on leafy brown algae (Sargassum and Dictyota). Sometimes in large aggregations.