Ostorhinchus compressus reaches 12 cm. Indo-Pacific cardinalfish with laterally compressed body (hence compressus) metallic blue-green with distinctive black-white longitudinal line on flanks and large red eye. Lives in dense schools from 1 to 20 m under table corals and shallow coralligenous of central and western Indo-Pacific. Nocturnal, comes out to hunt zooplankton at night. Male mouth brooding. Classic macro photo subject of shallow coral dives.

