These are common on lagoon and seaward reefs, but among the easiest places to see them are in the sand and rubble bottoms of seaward reef surge channels. Males differ from females in having a tall, vertically banded anterior dorsal fin that they erect when trying to woo females, as in the first photo.
The short dorsal fin of the female is erect in the next two photos below.
Another male trying to impress a female.
The next two photos show small juveniles, the upper one already with more adult coloration.
Created 28 September 2017