The Atlantic wolffish (Anarhichas lupus), also known as the seawolf, Atlantic catfish, ocean catfish, devil fish, wolf eel (the common name for its Pacific relative), woof or sea cat, is a marine fish of the wolffish family Anarhichadidae, native to the North Atlantic Ocean. The numbers of the Atlantic wolffish in US waters are rapidly being depleted, most likely due to overfishing and bycatch, and it is currently a Species of Concern according to the U.S. National Oceanic and Atmospheric Administration's National Marine Fisheries Service.

Apart from their unique appearance wolffish are distinguished by the natural antifreeze they produce to keep their blood moving fluidly in their very cold habitat, involvement by both the male and female in brood bearing, and the large size of their eggs. They are also an important factor in controlling green crab and sea urchin populations, which can become overly disruptive to habitats if left unchecked. Wolffish population success is also an important indicator of the health of other bottom-dweller populations, such as Atlantic cod.