A large blue-grey triggerfish that blows jets of water at sand to uncover prey, and defends a nest by charging.
To about 55 cm, deep-bodied, blue-grey to olive with fine blue lines on the head and yellow margins to the fins, becoming darker and plainer with age. Juveniles are boldly marked and look like a different fish.
It feeds by turning over rubble and blowing jets of water at the sand to uncover prey, and it will take urchins by flipping them. Like every large triggerfish it guards a nest by defending a cone of water above it, and a female on a nest will charge. The way out of that cone is sideways and level rather than upward, since swimming up keeps you in it. Outside the breeding season it is wary and moves off before a diver gets close.
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.