ling, (Molva molva), in zoology, commercially valuable marine fish of the cod family (Gadidae), found in deep northern waters near Iceland, the British Isles, and Scandinavia. The ling is a slim, long-bodied fish with small scales, a long anal fin, and two dorsal fins, the second being much longer than the first. A large, mottled, brown or greenish fish, the ling may grow to a length of about 2 m (almost 7 feet). It is related to two other deepwater European fishes: the Spanish, or Mediterranean, ling (M. macrophthalma, or M. elongata) and the blue ling (M. dypterygia, or M. byrkelange).