Carp Fish: Common Carp ID, Types, Eating and History

• Barbels (whiskers): Two barbels on each side of the upper jaw.
• Dorsal fin: Saw-toothed spines precede the dorsal and anal fins.
• Scale type: The scales of the back and sides are prominently dark-edged, creating a crosshatched effect.
• Body shape: A moderately deep, stout-bodied fish, with a high back and large scales.
• Coloration: The back and sides are brassy olive, and the belly is yellowish white.

Unlike the similar goldfish, the common carp has two barbels on each side of the mouth and a long dorsal fin; the goldfish has no barbels at all.

The native bigmouth buffalo looks like a carp but lacks barbels entirely.

Most abundant in large streams and impoundments, especially those made fertile by runoff and discharge of agricultural and domestic wastes. Not native to North America; introduced in 1877 by state fish commissions.

Lay the fish flat on its side in even light and photograph the whole body first, then the details below. Get a close, sharp frame of the head: mouth, jaw length and any barbels. Raise the dorsal and anal fins fully; ray counts and fin edges only read when the fin is spread. Photograph the gill cover and cheek straight on so the ear flap and scale rows are visible. Shoot the side of the body before the fish dries; spots and stripes fade fast out of water. The app reads the photo and names the likely species; use the marks on this page to confirm it.

Size and daily limits for this species differ by state and by water, and some waters are catch-and-release only. Check the current regulations for where you are fishing before keeping any fish; if you are unsure of the species, release it.

Carp is a name for several fish in the family Cyprinidae, a very large group mostly native to Eurasia (Wikipedia). The ones people mean most often:

• Common carp (Cyprinus carpio): the carp of American rivers and lakes, and of European fishing lakes; mirror and leather carp are domesticated forms with fewer scales
• Asian carps: silver, bighead, grass and black carp, domesticated in East Asia
• Crucian carp, koi and goldfish, which are also carps

Pennsylvania's Fish and Boat Commission describes the common carp as native to Asia and spread through Europe by the Romans. If you have a carp-shaped fish and are not sure which, check the mouth first: the common carp has two barbels on each side of the upper jaw, and the goldfish has none.

Wikipedia gives a typical common carp as 40 to 80 cm (16 to 31 in) and 2 to 14 kg, with a record of 45.59 kg (100.5 lb) caught in 2013 and a documented age of 64 years for a fish of wild origin. The Pennsylvania Fish and Boat Commission says that in most waters a 10 lb carp could be considered small and fish over 20 lb are not uncommon.

Carp are omnivores that feed on the bottom. They take mouthfuls of sediment, sort food by taste and size, and push the rest back out, which is why water with many carp turns cloudy (Wikipedia). They eat plants and seeds but prefer insects, crustaceans, molluscs, worms and fish eggs. A typical female lays 300,000 eggs in a single spawn and can lay more than a million in a year.

Carp were brought in on purpose. MeatEater's history of carp says the US Fish Commission, set up in 1871, distributed 2.5 million pounds of carp between 1879 and 1896. Sources date the first stocking slightly differently: the Pennsylvania Fish and Boat Commission says the late 1870s, the Missouri Department of Conservation 1877, and Wikipedia the 1880s.

At first it worked. By 1908, according to MeatEater, commercial fishermen were landing more than 40 million pounds a year, and carp appeared on upscale hotel menus at prices matching halibut. Then its reputation fell: once carp became cheap it was labelled poor man's food, and by the 1930s the commercial catch had dropped by more than 97% even as wild populations kept growing. Carp were also blamed for dirty water, though MeatEater argues they were simply surviving where other fish could not.

Much of the world eats carp. Wikipedia says common carp contributed about 4.67 million tons in 2015 to 2016, roughly 7.4% of global inland fisheries production, and that carp have been farmed in China for at least 2,400 years. Breaded and fried carp is part of the traditional Christmas Eve dinner in Slovakia, Poland, the Czech Republic and eastern Croatia.

In the US the reasons are mostly reputation and history rather than the fish: the poor man's food label and the association with polluted water described above. Wikipedia notes carp are still considered trash fish and invasive pests in most of the United States.

Carp are bottom feeders and can live for decades, so for a wild carp, check your state's consumption advisory for that water before eating it.

Carp and tilapia are different fish. Carp are cyprinids from Eurasia; tilapia is the common name for nearly a hundred species of cichlid fish native to Africa and the Middle East (Wikipedia). Both are major farmed fish, which is where the confusion comes from.

Carp are not predators of people, and none of the sources on this page describe them as aggressive. The harm they do is to habitat: their bottom feeding muddies the water, and Wikipedia notes they are considered invasive pests in most of the United States. For anglers, the Pennsylvania Fish and Boat Commission says carp fishing is making a comeback in the US, with a growing tournament scene.

The English name for Cyprinus carpio is the common carp, also called the European carp, the Eurasian carp or simply carp (Wikipedia). FishBase uses common carp. Domesticated forms have their own names: the mirror carp has a few large scales, the leather carp is almost scaleless, and koi is the ornamental variety that originated in Japan in the 1820s (Wikipedia). The US Geological Survey adds the Israeli carp as another strain. All are the same species; the fish once called the Amur carp is now usually treated as a separate species, Cyprinus rubrofuscus (Wikipedia).

Wild common carp are native only to rivers draining to the Black, Caspian and Aral seas (FishBase); the US Geological Survey describes the species evolving in the Caspian basin and spreading naturally east into Asia and west as far as the Danube. Those wild native populations are now considered vulnerable, threatened by river regulation and by mixing with farmed stock (Wikipedia; FishBase), even though FishBase shows the species as a whole as Least Concern (IUCN, assessed 9 June 2022).

Everywhere else it is introduced. The US Geological Survey records it as established in more than 50 US states and territories, including Alaska, Hawaii and Guam, with early records from California (1872), Colorado (1879) and Arizona (1885). It is on the list of the world's 100 worst invasive species (Wikipedia), and FishBase flags it as a potential pest.

Carp figures differ from source to source, so here they are side by side:

• Maximum length: 129 cm (FishBase); 122 cm (US Geological Survey); 120 cm (Wikipedia)
• Common length: 31 cm (FishBase); a typical 40 to 80 cm (Wikipedia)
• Maximum weight: 40.1 kg (FishBase); record fish 45.59 kg, or 100.5 lb (Wikipedia)
• Maximum age: 38 years (FishBase); 64 years for a wild-origin fish in North America (Wikipedia)
• Water: 3 to 35 C, pH 6.5 to 9.0, fresh or brackish, 0 to 29 m deep (FishBase)
• Spawning: in shallow, weedy water at 15 to 20 C; eggs hatch in about 4 days (FishBase)

FishBase also notes carp are most active at dusk and dawn.

Grass carp are a different species (Ctenopharyngodon idella), not Cyprinus carpio, and many US states restrict them because they eat so much plant life and can breed in the wild. Wikipedia says grass carp can eat up to three times their own body weight a day, and in 2013 they were confirmed to be reproducing in the Great Lakes basin. They reached the US in 1963, imported from Taiwan and Malaysia to fish farms in Alabama and Arkansas; some escaped from a federal facility in Stuttgart, Arkansas, in 1966, and they have now been reported in 45 of the 50 states.

The compromise is the triploid grass carp, a sterile fish that cannot reproduce but still clears weeds, which many states still allow for stocking (Wikipedia). What is allowed, and whether you need a permit, differs by state, so check with your state's fish and wildlife agency before stocking any carp in a pond.