Place of origin:Central Pacific
Widespread Indo-West Pacific. Coastal to outer reefs at depths from 6m down to moderate depths, but usually outer reefs along walls at about 25m depth. Forms small schools, sometimes females and males in separate aggregations or mixed. Highly variable in colour, locally and geographically, and also in the size of the male's pale blotch (looks blue in natural light). This varies from being totally absent to almost half the body size, especially when showing nuptial colours. The presence or size seems to be in relation to the presence of other species living on the same reefs, or the density of populations, and in some populations only shows during spawning. Length to 16cm.