Peppered Squirrelfish

The family splits in two at dinner, and this is the half that eats off the bottom.

Squirrelfish and soldierfish look alike, hide in the same caves and come out at the same hour, but they leave in different directions. The soldierfish rise into open water above the reef and pick plankton out of the current all night. The squirrelfish go down onto the substrate and hunt what walks there: crabs, shrimps, small brittle stars, worms, taken one at a time off sand and rubble in the dark.

That difference is written into their heads. Plankton feeders have upturned mouths, bigger eyes for their size and finer gill rakers; the bottom hunters have heavier jaws, blunter snouts and the equipment for crunching a crab. It is a clean case of two closely related groups sharing a daytime hiding place and dividing up the night.

This one works shallower ground than most of its relatives, rocky shallows and surge channels rather than coral, and it is the plain member of the family: silvery-white finely peppered with dark rather than banded in red. Usually around thirteen centimeters, occasionally much larger.