Wolffish (genus Anarhichas)

FishMarineCold water

Overview

Wolffish (genus Anarhichas) are large, heavy-bodied, eel-like fish of cold northern seas, named for the wolfish set of fangs at the front of their jaws. Behind those prominent canine-like front teeth lie rows of strong, blunt crushing and grinding teeth, all of which the wolffish puts to use cracking open the hard-shelled animals it eats. The Atlantic wolffish (Anarhichas lupus), shown here, is the best known, with a blunt, almost dog-like face and a long, tapering body.

Living in chilly waters where temperatures can dip below the freezing point of ordinary body fluids, wolffish produce natural antifreeze proteins in their blood that stop ice crystals from forming, letting them thrive in the cold.

Note: “wolffish” covers a few Anarhichas species; details here use the Atlantic wolffish as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Wolffish live in cold waters of the North Atlantic and North Pacific, typically on the seabed at moderate to considerable depths, around rocky reefs, boulder fields, and cold, hard bottoms where their shellfish prey is abundant. The Atlantic wolffish favours rocky habitats on continental shelves, often sheltering in crevices and dens.

Diet

Wolffish are carnivores specialising in hard-shelled prey: sea urchins, crabs, clams, mussels, whelks, and other molluscs and echinoderms, which they crush with their formidable teeth. The front fangs grip and wrench prey loose, while the heavy back teeth grind shells to pieces — so effective that wolffish help control sea urchin numbers, which in turn benefits kelp and other seabed habitats. They replace and regrow their worn teeth.

Behavior

Wolffish are generally solitary, sedentary bottom-dwellers that lurk among rocks and in crevices, ambushing or seeking out shellfish across the seafloor. Their standout adaptation is biochemical: they make antifreeze (glycoprotein) molecules that circulate in the blood and bind to tiny ice crystals, preventing them from growing — a vital trick for a fish living near freezing. Unusually for fish, Atlantic wolffish have internal fertilisation, and the male guards the large clutch of eggs for months until they hatch, a notable degree of parental care. Despite their fierce-looking fangs, wolffish are not aggressive toward people and use their teeth on shellfish, not swimmers.

Human Interaction & Conservation

Wolffish are caught for food (sometimes sold as “ocean catfish”) and have been heavily affected by trawling and bycatch, and because they are slow-growing, late-maturing, and tied to specific rocky habitats and egg-guarding sites, some populations — including the Atlantic wolffish in parts of its range — have declined and are of conservation concern, with protections in some areas. As an important predator of sea urchins, the wolffish also matters for healthy seabed ecosystems. Consult authoritative sources for current status.

More photos of the wolffish