Dark at the front and pale behind, holding a small territory on the reef and driving off anything that enters it.
To about 10 cm. Three adult patterns occur: black over the front half with a white soft dorsal and tail base; blackish above with orange below; or a white head and body with a blackish tail base. The sharp front-to-back break is the constant. Unusually for this family the juvenile looks like the adult.
The dusky damselfish is the confusion and it is uniform grey-brown, where this fish is sharply two-toned.
Nought to a hundred metres, on shallow coral reef and on deeper isolated patch reefs. It is aggressively territorial but only over a very small area, so unlike some of its relatives it will not meaningfully harass a diver. It lives to thirteen years, which is a long time for a 10 cm fish. Sources disagree on the diet: one gives algae, another plankton.
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.