The stippled gunnel was first formally described as Blennius dolichogaster in 1814 by the German zoologist and botanist Peter Simon Pallas with its type locality given as Kamchatka.

[3] In 1836 Achille Valenciennes described a new species Gunnellus ruberrimus from the Kuril Islands and in 1896 David Starr Jordan and Barton Warren Evermann designated G. ruberrimus as the type species of the new genus Rhodymenichthys.

[5] The stipple gunnel's generic name Rhodymenichthys is a combination of Rhodymenia, a genus of red seaweed, assumed to be a reference to the cherry-red colour of the body and fins as well as the occurrence of this species in beds of that seaweed, with ichthys the Greek for "fish".

It has a highly variable body colour which may be brown, green or pale purple and there is a thin silvery horizontal band which runs from the eye to the base of the pectoral fin.

[2] The stippled gunnel is found in the North Pacific Ocean from Niigata and Iwate Prefectures in Japan to Primorskii Krai, Sakhalin and the Commander Islands in Russia.