The ling is the largest member of the cod family of fishes. It sometimes attains a length of 7 feet and can weigh more than 120 pounds. Found mostly in the waters around Great Britain, ling is a rich source of liver oil and the flesh is sometimes fine enough for it to be sold as cod. Ling is usually salted and dried before being sold. It must be soaked in cold water before cooking and should be cooked slowly until very tender.