Feeds almost exclusively on Acropora polyps and swims in pairs, snout-down.
A small filefish to about 12 cm, pale blue-green covered in rows of round orange spots, with a long upturned snout and a black blotch on the caudal fin. Nothing else in the region carries this combination. The snout is the working end of an unusually narrow specialisation: the species feeds almost entirely on the polyps of branching Acropora, picking them individually, and it takes on the coral’s chemical signature in its own tissue closely enough that predators have been shown to have difficulty detecting it by smell.
Occurs in pairs, occasionally in small groups, hanging head-down among the branches of living coral and rarely more than a fin’s length from it. The dependence on one coral genus makes it an early casualty of bleaching: local populations disappear where Acropora dies and do not return until it does. Recorded from the shallows to about 30 m. On a muck site it is a fish of the coral patches rather than the sand, and it drifts steadily away from an approaching diver while never quite leaving the thicket, which is what makes it harder to photograph than its abundance suggests.
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.