Indo-West Pacific: Red Sea and East Africa to Japan, south to New Caledonia.

Species of Diagramma differ from Plectorhinchus by having a much longer and narrower caudal peduncle and fewer dorsal fin spines. Juveniles yellow or white with broad black stripes and anterior part of dorsal fin tail. Adults become plain grey or spotted. The Queensland fish are plain grey.

Typically found on open muddy or silty substrates in protected bays or estuaries. Also in shallow coastal areas and coral reefs.