The largest parrotfish, and one of the few fish that visibly rebuilds a reef.
To about 130 cm and 45 kg, dull blue-green with a squared-off head that develops a heavy forehead bump in adults, and a pale pink to green face. Juveniles are brown with pale spots and look nothing like adults. Nothing else in the region approaches the size, and a large individual is unmistakable at any distance.
It bites living coral directly, using the bump to ram heads apart and fused teeth to take chunks, then grinds the skeleton and passes it as sand — an adult processes on the order of several tonnes of reef material a year. Groups of ten to fifty sleep in caves and shallow lagoon areas and disperse at first light, which is why encounters are most reliable on early dives. The species is heavily fished across its range and is listed as vulnerable; numbers in the Coral Triangle are patchy, and it is common in Papua New Guinea and scarce in the Indonesian and Philippine muck destinations. Recorded from about 3 to 30 m.
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.