The Murray Cod (Maccullochella peelii) is the largest freshwater fish in Australia. Despite its name, it is not a member of the cod family, but belongs to one of the families of Perciformes. There are a number of subspecies of M. peelii; strictly speaking the Murray Cod is M. peelii peelii, other subspecies having other common names.

The Murray Cod is named after the river in which it is found. Murray Cod are widespread throughout the Murray-Darling Rivers system in Eastern Australia, becoming scarcer towards the East. They have declined in abundance over the past 50 years because of overfishing and environmental factors. Many Aboriginal myths describe the creation of the river system (or indeed all river systems of Australia) by a gigantic murray cod ploughing through the earth to escape from a hunter, or hunters. In some stories the cod is caught and chopped up to create all the fishes of the river. Its head is kept intact, and it is decreed no Murray Cod may outgrow that size.

Murray cod possess a cream to olive green colour with dark grey to greenish blotches over the head and body. Adult fish are commonly 60cm in length, but can grow up to 180cm may weigh up to 118kg. They have a preference for slow moving, murky water and are very territorial. They are prized as a game fish.

The Murray Cod is a predator that eats almost anything smaller than itself including crustaceans such as yabbies, shrimp and crayfish, and fishes such as carp, goldfish, redfin , bream, catfish, Golden Perch , Western Carp , gudgeon and even other cod. It has also been known to eat ducks, cormorants, grebes, tortoises, water dragons, snakes, mice, frogs and mussels.

Murray Cod spawn in shallow waters, reaching sexual maturity at 4 or 5 years of age. They may live for 50-60 years.