Body elongate, oval; snout short, with prominent hump just below eye; mouth small, protrusible, low on head; teeth small, conical, tips slightly depressed & either smooth or with multiple small points; dorsal fin VI, 26-27; anal II, 27-29; pectoral 17-19 rays; pelvics I, 3; 2 pairs of cutting keels on plates on narrow tail base; tail straight to slightly rounded, with long filament from each corner; scales very small, rough; lateral line complete.
Yellow-brown, with irregular thin blue bars along flank, and small blue spots above and below bars and on head; broad blue band before eye; lips blue; dorsal and anal yellow-brown with thin blue margins; tail dark, yellow rear border, filaments blue; male can change color to overall brilliant blue; juveniles brown with scattered small dark spots.
Size: 60 cm.
Habitat: rocky and coral reefs; juveniles benthic on sheltered habitats and rubble slopes; adults in midwater near exposed reef fronts.
Depth: 1-50 m; juveniles usually 5-15 m; adults usually 10-25 m.
An Indo-Pacific species; recorded as a vagrant from the Galapagos Islands.