Other common names: Oriental carp, European carp, common carp, koi. Carp are carp fish cooking large freshwater fish native to central Asia.

Introductions in many countries have helped to make carp the most widely distributed freshwater fish in the world. They are extensively farmed in Europe, Asia and the Middle East, and are a popular angling fish in Europe. However, in North America, Canada and Australia, carp are considered a significant pest. Carp are very versatile, and can live in a great variety of habitats including highly degraded areas. Over the past few decades carp have spread across most of south-eastern Australia. They are now the most abundant large freshwater fish in some areas, including most of the Murray-Darling Basin, and are thought to have contributed to the degradation of our natural aquatic ecosystems.

The scales are large and thick. In the wild they are usually olive green to bronze or silvery in colour with a paler underside. All strains belong to the same species, Cyprinus carpio. Carp can grow to a very large size, with overseas reports of fish as large as 1. 2 metres in length weighing 60 kg. Fish of up to 10 kg have been caught in Australia, but weights of around 4-5 kg are more common.

Habitat: Carp are usually found in still or slowly flowing waters at low altitudes, especially in areas where there is abundant aquatic vegetation. They are also found in brackish lower reaches of some rivers and coastal lakes. They are capable of tolerating a range of environmental conditions. They have a greater tolerance of low oxygen levels, pollutants and turbidity than most native fish, and are often associated with degraded habitats, including stagnant waters. Changes to water flows, declining water quality and other changes to river habitats over the past few decades have negatively affected many native fish while favouring carp.

Reproduction: Under suitable conditions, carp are highly prolific. Carp migrate to and from breeding grounds during the breeding season, sometimes travelling hundreds of kilometres. Most eggs and larvae die before they reach adulthood, although more may survive if environmental conditions are suitable. Floods seem to provide especially favourable conditions for carp breeding as well as abundant food for juveniles. This may help explain why carp experienced such a population explosion during the large floods of the 1970s.

Feeding: Carp are omnivorous, and their diet varies depending on what is available. They consume a range of small food items such as molluscs, crustaceans, insect larvae and seeds. Carp rarely eat fish, but may consume fish eggs and larvae and disturb breeding sites. Adult carp have no natural predators. Large predatory native fish, such as Murray cod, golden perch and bass, may consume juvenile carp, although it appears they are not a favoured prey item. Carp have been introduced into Australia both deliberately, in an attempt to imitate the European environment, and accidentally, through the escape of ornamental or aquaculture fish.

In Victoria, the stocking of carp began as early as 1859, but early stocking attempts were not successful. In NSW, the earliest known introductions occurred near Sydney in 1865. Yanco’ strain became established in the Murrumbidgee in the early part of the 20th century. Basin since at least the 1920s, although for some time they remained fairly uncommon. In the early 1960s a new strain was imported for aquaculture and reared at a fish farm in Boolarra. These carp were stocked into farm dams near Mildura and soon spread up the Murray and Darling Rivers, assisted by widespread flooding in the mid 1970s.