A shallow-water surgeonfish of surge zones, and aggressive towards its own kind.
To about 38 cm, with a yellow to orange upper body ruled with blue and black horizontal stripes edged in black, a pale blue-grey belly and a deeply lunate tail. Like all surgeonfishes it carries a hinged blade on each side of the caudal peduncle; in this species the blade is large and venomous, and a mishandled fish can cut deeply.
It lives in the top few metres where surge is strongest, holding and defending feeding territories against other surgeonfishes, and grazes filamentous algae from hard substrate. Males are strongly territorial and chases are frequent. Photographs are difficult mainly because of the water movement rather than the fish, which pays little attention to divers. Recorded from the surface to about 15 m and rarely deeper.
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.