Triacanthodes ethiops was first formally described in 1894 by the British physician, naturalist, and carcinologist, Alfred William Alcock, with its type locality given as the Bay of Bengal at 13°51'12"N, 80°12'12"E, Investigator station 162, from a depth of 145–250 fathoms (870–1,500 ft; 265–457 m).

[3] The fifth edition of Fishes of the World classifies the family Triacanthodidae in the suborder Triacanthoidei in the order Tetraodontiformes.

[5] Triacanthodes ethiops has six spines and 15 or 16 soft rays supporting the dorsal fin.

This species has a maximum published standard length of 9.4 cm (3.7 in).

[6] Triacanthodes ethiops has an Indo-West Pacific distribution and has been recorded to be found in East Africa, the Maldives, Japan, the East China Sea, Philippines, Indonesia, New Caledonia, and Australia.