A copper-bronze fish shaped like a wedge, deep at the head and tapering to a narrow tail, with an eye far too large for daylight. Whole caves fill with them, hanging in a slow shoal that opens and closes around a diver without ever quite breaking, and the black-edged anal fin flickers as they turn.
The eye explains the schedule. Sweepers spend the day packed into overhangs, wrecks and cave mouths, and spill out after dark to feed on zooplankton in open water, returning before dawn. A wreck that looks empty at noon can be solid with them in the beam of a night dive.
They are also one of the fish a diver hears before seeing. Members of this family make sound with the swim bladder and can produce audible clicks and drumming inside a cave, a wall of small noises from an animal most people never notice making any.
- deep body sloping steeply from a large eye to a narrow tail
- coppery bronze with a black edge on the anal fin
- packs a cave in a slow, tightly spaced shoal
- length up to 20 cm
