Lythrichthys was first described as a genus in 1904 by the American ichthyologists David Starr Jordan and Edwin Chapin Starks as a monotypic genus for Lythrichthys eulabes which they described with a type locality given as off Ose Point in Suruga Bay in Japan.

[1] The genus name is a compound of lythrum, which means "gore", alluding to red colour of the body of living L. eulabes, and ichthys, Greek for "fish".

[4] The following 5 species are classified within the genus Lythrichthys:[3] Lythrichthys deepwater red scorpionfishes are characterised by typically having 3 spines and 5 soft rays in the anal fin, although there may be as few as 4 or as many as 6 anal soft rays/ they have 7-12 predorsal scales.

The tip of the first lacrimal spine just extends over the upper lip< the scales on the thorax and abdomen are clearly embedded in the skin.

[5] Lythrichthys deepwater red scorpionfishes are found in the Indo-West Pacific as far north as Japan and south to Australia and west as far as Fiji.