Jonah's Icefish

Jonah's icefish has a forward curving spine on the snout. There are 3–4 radiating ridges on the operculum, each ending at its rear with a spine; none of the other opercular bones have spines. The three lateral lines do not have any bony plates. The first and second dorsal fins are continuous. The dorsal fins hold 14–15 spines and 32–35 soft rays while the anal fin contains 29–32 soft rays. The well-developed first dorsal fins and fan-shaped pelvic fins are blackish while the other fins may be dusky or blackish in color. The overall color is a dark blackish-green or black on the body, although the belly is whitish; those of juveniles may have irregular dark markings present. This species attain a maximum total length of 56 cm (22 in).

Jonah's icefish is found in the Southern Ocean where it is circum-Antarctic on the continental shelf and slope, with the northernmost reports coming from the South Shetland and South Orkney Islands. It is a benthopelagic species which occurs at depths between 20 and 900 m (66 and 2,953 ft). In January 2014 the first nesting Jonah's icefish records were made, and in February 2021 a larger colony estimated to be composed of approximately 60 million Jonah's icefish was found, both colonies were discovered inhabiting the Filchner Trough in the southern Weddell Sea, off the coast of Antarctica between 420 to 535 metres (1,378 to 1,755 ft). It is estimated that the colony discovered in 2021 covers at least 240 square kilometres (93 sq mi), with an average of one nest every 3.85 square metres (41.4 sq ft) and a total biomass of 60,000 tonnes (132,000,000 lb) of fish.