Cod called cod: "Cod" forms part of the common name of many other fish no longer classified in the genus "Gadus". Many are members of the family Gadidae; others are members of three related families within the order Gadiformes whose names include the word "cod": the morid cods, Moridae (100 or so species); the eel cods, Muraenolepididae (four species); and the Eucla cod, Euclichthyidae (one species). The tadpole cod family (Ranicipitidae) has now been placed in Gadidae. Gadiformes include: Some fish have common names derived from "cod", such as codling, codlet or tomcod. ("Codling" is also used as a name for
Atlantic cod currents and develop into larvae ("fry"). Age of maturation varies between cod stocks, from ages two to four in the west Atlantic, but as late as eight years in the northeast Arctic. Cod can live for 13 years or more. The Atlantic cod is one of three cod species in the genus "Gadus "along with Pacific cod and Greenland cod. A variety of fish species are colloquially known as cod, but they are not all classified within the "Gadus", though some are in the Atlantic cod family, Gadidae. Atlantic cod are a shoaling species and move in large, size-structured aggregations.