The burbot (Lota lota) is the only gadiform (cod-like) freshwater fish. It is also known as bubbot, mariah, freshwater ling, the lawyer, coney-fish, lingcod, freshwater cusk, and (confusingly) eelpout. The species is closely related to the marine common ling and the cusk. It is the only member of the genus Lota. For some time of the year, the burbot lives under ice. They require frigid temperatures to breed. (source)