Yellow front, blue back, and never out in the open for long.
A dwarf angelfish to about 15 cm, cleanly divided: bright yellow head and tail, deep blue middle, and a blue bar over the eye. Nothing else in the region carries the same split, and the only difficulty is that the fish is almost never still — it moves between coral heads in short darting runs and turns side-on into a crevice as soon as a diver stops.
It lives in small groups of a male and several females over rubble and coral, feeding on algae and small invertebrates. Photographing it is a matter of picking one coral head, settling, and waiting for the circuit to come back round rather than following. Recorded from around 5 m to about 40 m, and generally more numerous at the lower end of that range where rubble meets reef.
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.