Yellow above with five black bars, in loose shoals over almost any hard bottom. Males turn dark blue while guarding a purple egg patch on rock.
To about 23 cm. Silvery with a yellow cast over the upper back and five black bars that are narrower than the pale spaces between them. Juveniles are silvery-white with thinner bars and yellow on the upper body and dorsal fin, and live in tide pools, seagrass, mangroves and around floating debris.
The night sergeant is the confusion, and the bar width settles it: wider than the pale spaces there, narrower here. The night sergeant also has a prominent black spot at the upper pectoral base.
Nought to twenty metres, usually the top ten, along reef edges, in feeding aggregations that can run to several hundred fish over shallow reef tops. A nesting male turns dark blue or purple and guards a red-purple patch of eggs for about a week; territories are held only for spawning and brood care, not permanently.
It is unafraid of divers and comes readily to anything being fed, which is how most people meet it.
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.