Juveniles inhabit shallow sheltered areas, while adults prefer coastal reefs that offer ample hiding places at depths of up to 40 m. They feed on sponges, tunicates and algae. They have a laterally compressed, oval body and a preopercular spine. The colouring of adults is mostly electric blue with some light blue spots. Their dorsal and anal fins have a yellow-tipped filament.

Their colouring varies according to age. Juveniles are dark blue with light blue semi-circular lines alternating with white ones. The change to adult colouring occurs when individuals are between 8 and 16 cm long.

Conservation status