Terminal males are blue-green with a bright blue chin and a yellow saddle; initial-phase fish are plain yellow-brown.
To 75 or 90 cm depending on the source, commonly 30, which makes it one of the largest of its genus. Initial-phase females are yellowish to yellowish-green with about five irregular pale blue-white bars down the body. Terminal-phase males have blue-green backs with salmon-pink scale edges, mostly salmon-pink lower sides, dark green bands around the mouth and eye, and a pair of blue bands on the chin, which is the name. The tail is rounded in small females and grows long lobes in large males.
The ember parrotfish is the confusion. Its terminal-phase males are sharply two-toned, dark in front and light behind, with a distinctly squared snout, where this species is evenly blue-green with salmon scale edges and a rounded snout.
It grazes shallow reef and adjacent sand and rubble between 1 and 90 m, often in loose groups. It is also known as the blue-barred parrotfish, after the pale bars on the females; both names are in common use for the same fish. The Galapagos record is well established. The Revillagigedo record is real — including a museum specimen from Clarión collected in 1925 — but it sits at the edge of the range and neither of the two main reference works mentions 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.