Body elongate; 3 primary color phases, the smallest with a black mid-lateral stripe which continues as pale red blotches on head; back above stripe yellow on reef fish and whitish on fish from inshore non-reef areas, and body below white. The largest phase, has a bright blue head and a green body with two broad vertical black bars anteriorly which are separated by a light blue interspace; this phase is always male. The small yellow phase with the black stripe may be either male or female (Ref. 13442).