Juveniles shelter in anemones alongside anemonefish; adults leave and turn plain black.
Juveniles are black with a white spot on each side of the upper body and a third on the forehead — the three spots — and are about 2 cm when they first settle. Adults reach about 14 cm, lose the spots progressively and end plain sooty black to dark grey with a paler snout.
Juveniles live among the tentacles of sea anemones, including hosts occupied by anemonefish, and are tolerated there; they also use urchins and branching coral. Adults leave the anemone and form loose groups around coral heads and rubble, feeding on zooplankton. Because juveniles sit in an anemone that a diver is already photographing for its anemonefish, they are among the most frequently recorded reef fish here. Recorded from the shallows to about 40 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.