Hoplichthys, the ghost flatheads, is a genus of marine ray-finned fishes native to the Indian and Pacific Oceans.

[1] In 1873 the German naturalist Johann Jakob Kaup considered that the genus Hoplichthys was so different from other "flathead" taxa that it merited placing in a monogeneric family, the Hoplichthyidae.

[4] However, some workers have put forward evidence that there may be a rather surprising sister group relationship between this family and the gobies as they share more seemingly unique derived characters with each other than with other taxa, this needs to be further investigated,.

There is series of large bony plates on the body of H. langsdorfii, each of which bears two spines and this is thought what the first part of the genus name refers to.

The majority of the species are yellow, pinkish, or brown in colour on the upper body and flanks, with various spots and mottles, and they are pink, white or silver ventrally.

The pectoral fins vary in colour from yellowish brown to hyaline marked with crossbarring, spotting or mottling.