This article is about codfish; for other meanings, see COD.

Cod is the common name for the genus Gadus of fish, belonging to the family Gadidae, and is also used in the common name of a variety of other fishes. Cod is a popular food fish with a mild flavor, low fat content, and a dense white flesh that flakes easily. Cod livers are processed to make cod liver oil, an important source of vitamin A, Vitamin D, it is and omega-3 fatty acids (EPA and DHA).

Species in genus Gadus

At various times in the past, a very considerable number of species have been classified in this genus. However the great majority of them are now either classifed in other genera, or have been recognised as simply forms of one of three species. Modern taxonomy, therefore, recognises only three species in this genus:

• Atlantic cod Gadus morhua
• Pacific cod Gadus macrocephalus
• Greenland cod Gadus ogac

All these species have a profusion of common names, most of them including the word "cod". Many common names have been used of more than one species, in different places or at different times.

Related species called cod

Cod forms part of the common name of many other fish not longer classified in the genus Gadus. Many of these are members of the family Gadidae, and several were formerly classified in genus Gadus; others are members of three related families whose names include the word "cod", the Morid cods, Moridae (100 or so species), the Eel cods, Muraenolepididae (4 species), the Eucla cod (Euclichthyidae) (1 species). The Tadpole cod family (Ranicipitidae) has now been absorbed within Gadidae.

Species within the order Gadiformes that are commonly called cod include:

• Arctic Cod Arctogadus glacialis
• East Siberian Cod Arctogadus borisovi
• Saffron Cod Eleginus gracilis
• Polar Cod Boreogadus saida
• Rock Cod Lotella rhacina
• Poor Cod Trisopterus minutus
• Pelagic Cod Melanonus gracilis
• Small-headed Cod Lepidion microcephalus
• Tadpole Cod Guttigadus globosus
• Eucla Cod Euclichthys polynemus

Some other related fish have common names derived from "cod", such as codling, codlet or tomcod (note that "codling" is also used as a name for a young cod).

Unrelated species called cod

However there are also fish commonly known as cod that are quite unrelated to the genus Gadus. Part of this confusion of names is market-driven. Since the decline in cod stocks has made the Atlantic cod harder to catch, several replacements are marketed under names of the form "x cod", and culinary rather than phyletic similarity has governed the emergence of these names. A very large number of fish have thus been named as some kind of cod at some time. The following, however, seem to have well established common names including the word "cod"; note that all are Southern Hemisphere species.

Order Perciformes:

• Eastern Freshwater Cod Maccullochella ikei
• Murray Cod Maccullochella peelii
• Trout Cod Maccullochella macquariensis
• Sleepy Cod Oxyeleotris lineolatus
• Blue Cod Parapercis colias
• The cod icefish family, Nototheniidae, including:
  • Black Cod Paranotothenia microlepidota
  • Maori Cod Paranotothenia magellanica
  • Antarctic Cod Dissostichus mawsoni

Rock cod, Reef cod, and Coral cod

Almost all the fish known as coral cod, reef cod or rock cod are also in order Perciformes. Most are better known as groupers, and belong to the family Serranidae. Others belong to the Nototheniidiae. Two exceptions are the Australasian Red Rock Cod, which belongs to a different order (see below), and the fish known simply as the Rock cod in New Zealand, Lotella rhacina, which as noted above actually is related to the true cod (it is a Morid cod).

Order Scorpaeniformes

• Ling Cod Ophiodon elongatus
• Red Rock Cod Scorpaena papillosa

Order Ophidiiformes:

The Tadpole cod family, Ranicipitidae, and the Eucla Cod family, Euclichthyidae, were formerly classified in this order, but are now grouped with the Gadiformes.

See also

• Bacalao
• Bacalhau
• Cod trade
• Cod War
• Overfishing
• Scrod