A grey fish with one orange bar behind the head, and a juvenile that is plain yellow.
To about 35 cm, grey-brown, usually paler over the front half, with a horizontal orange bar edged in blue-black running back from just behind the eye. The bar is the identification and is present in adults only. Juveniles are plain bright yellow and look like a small tang.
It grazes the algal film and detritus from sand and rubble as much as from hard substrate, which puts it on the open ground of muck sites rather than only on reef. Adults are usually alone or in small groups and can pale or darken markedly. Recorded from about 3 to 45 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.