The sweeper of these reefs specifically, described from local material in 1877 and easily confused with its wide-ranging cousin. The quickest separation underwater is the anal fin: this one lacks the black edge, and carries a dark patch on the shoulder instead.
Behavior is the same as the rest of the family, and it is the behavior that makes them worth a stop. A group hangs under an overhang in loose formation, all facing the same way, tilting head-down as the surge pushes through, and the whole assembly shifts as one when a diver's shadow arrives without any individual appearing to decide anything.
After dark the shoal disperses into open water to feed on plankton and reassembles before dawn, so the same crack in the reef holds fish night after night. On a night dive, the cave is empty and the water above it is not.
- coppery body without the black edge on the anal fin
- dark shoulder patch behind the gill cover
- hangs head-down under overhangs in dense groups
- length up to 20 cm
