Chocolate brown with a broad white band, feeding on plankton in aggregations off drop-offs rather than on coral.
To about 18 cm. A black body crossed by a broad white wedge with a yellow upper edge, and a white tail. Laterally compressed with a slightly elongated snout and a small protractile mouth.
Nothing in the Maldives is close. Its obvious counterpart, the pyramid butterflyfish, is a Pacific fish and does not reach the Indian Ocean, and that absence is itself the identification.
One to forty metres along outer reef slopes, drop-offs and current-swept edges. It forms large schools out in open water off the reef edge, sallying out to take plankton and returning, which is how it is normally seen — not on the reef at all. It pairs to breed. It does not eat coral.
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.