Scarus altipinnis is distinguished from its congeners in the genus Scarus by the possession of a slightly elongated middle ray in the dorsal fin of the terminal phase males.
[2] These males are patterned with green towards the tail and have tow bluish-green bars on their chins and similar coloured spots and lines around the eye and operculum.
The females, the initial phase, are brownish with a scattering of white spots while the juveniles are striped or mottled with an obvious yellow head.
This is an oviparous fish and the male and female form pairs to spawn.
[1] The biggest threat to Scarus altipinnis is commercial fishing, especially in Micronesia, and habitat destruction.