Habitat: Marine, reef-associated. Young usually in adjacent seagrass beds. Depth range 2 - 20 m. Natural History Notes: Non territorial, herbivore. Scrapes algae from algae and coral. Solitary or in small groups. Often rests on the bottom. Characteristics: Mature males : a reddish slash from the corner of the mouth to just behind the rear margin of the eye. Small yellow blotch with two or more small black spots in the shoulder region between pectoral-fin base and dorsal fin. Dark tips on the caudal-fin lobes. Fish bottle-green. Immatures and females : highly variable, white saddle-like spot across the dorsum just behind the last dorsal-fin ray. Juveniles : broad brownish stripe along the side just above mid-body, set off both above and below by narrow light lines, the upper pale and the lower distinctly white. Black blotch behind gill cover.