Carp are relatively broad, heavy-bodied fish, with a serrated (or toothy) spine on their back. Carp often grow 1 to 2 ft in length and weigh 1 to 8 pounds, but it is not uncommon for the common carp to reach 30-40 pounds. In adults, the mouth is terminal, which means it is located at the end of their face. Young carp have a mouth slightly under the pointed part of the face. Often there are two barbels at the corners of the mouth. The tail has two, rounded but deep lobes. Males have a slightly larger fin on their bellies, but otherwise males and females look very much alike. Color and exact form are extremely variable, but scales are always large and thick ( view examples).
Carp that have been specially bred to be extremely colorful are known in the pet trade as "koi" (rhymes with "boy"). Some people call them goldfish, but doing so confuses carp with their smaller, close relative, Carassius auratus.
Common carp can be found within each of the biogeographic regions, but are only native to Europe in the Palearctic region. Common carp have been widely introduced and are found worldwide except for the poles and northern Asia. (Froese and Pauly, 2002; Nelson, 1984)
Carp are freshwater fish that live their whole lives in pools in streams, lakes, and reservoirs. They prefer larger, warmer, slower-moving bodies of water with soft muddy bottoms, but they are tolerant and hardy fish that thrive in a wide variety of aquatic habitats. Carp may survive in harsh conditions such as water with little oxygen or water that has large changes in temperature, even temporary freezing.
Carp generally spawn in the spring and early summer in temperate areas (like Michigan, where there are cold and warm seasons). Carp can breed all year in the tropics. They gather together in shallow water with many plants. The females scatter their eggs in the water among the plants and then the males fertilize the eggs. This is called external fertilization because the male waits to fertilize the eggs until they are outside of the female's body. The eggs stick to whatever they fall on and begin to develop. A typical female (about 45 cm long) may produce 300,000 eggs; some fish may produce one million eggs over the breeding season. Larger females can generally produce more eggs. Depending on the water temperature, eggs take three or four days to hatch.
Males are typically large enough to spawn(also called sexually mature) at 3 to 5 years and females at 4 to 5 years.
Carp do not provide any care for their babies.
There is a report of a common carp living an astounding 47 years, probably in captivity. Other reports of 13 to 20 years are probably more typical.
Carp can typically be found living together in small groups called schools. Larger carp often live alone.
Carp are omnivores. They eat animals and plants living in the mud at the bottom of rivers and lakes. Newly hatched carp feed on algae and microscopic animals that drift in the water called zooplankton. As they get older and larger they feed on larger invertebrates like caddisflies, snails, and crustaceans. Adult carp are known to eat a wide variety of organisms including insects, crustaceans, worms, mollusks, fish eggs, fish remains, and plant tubers and seeds. Carp feed by sucking up mud from the bottom, selecting what they want to eat and then spitting out the rest. You can recognize places where carps have been eating by seeing depressions in the mud at the bottom of shallow water.
Carp have a special way of feeding that decreases the quality of the water they live in. They lower the number of plants and algae growing in the water by uprooting them, eating them, and making the water turbid (cloudy) so that fewer plants grow. They also excrete large amounts of nitrogen into the water through their wastes, which often makes the water less suitable for othrer fish
These fish are considered pests in most of the places where they have been introduced. Impacts on humans include: reduced water quality (because they stir up mud and make it hard for plants to grow) and decreases in more valuable game fish and waterfowl. Also, attempts to get rid of carp are very costly.
Carp are an important food fish throughout most of the world except for in Australia and North America where the fish is considered bad-tasting. The world catch rate of carp per year exceeds 200,000 tons. The more colorful carp, called Koi, are bred in captivity and sold as ornamental pond fish.
Carp are very common. They are hardy and have been used to stock lakes. However, they have a tendency to outlive and outreproduce native fish, competing with native fish for resources.
These fish often overwhelm any ecosystem where they are introduced, so people have tried to get rid of them. The most successful method involves killing all fish in the lake with a poison, and then re-stocking the desirable species.
Matthew Chumchal (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.
Baldry, I. 2000. "Effect of Common Carp (Cyprinus carpio) on Aquatic Restorations" (On-line). Accessed 2 April 2002 at http://www.hort.agri.umn.edu/h5015/00papers/baldry.htm.
Banarescu, P., B. Coad. 1991. Cyprinids of Eurasia. Pp. 127-155 in I Winfield, J Nelson, eds. Cyprinid Fishes. London: Chapman and Hall.
Brabrand, A., B. Faafeng, J. Nilssen. 1990. Relative importance of Phosphorus Supply to Phytoplankton Production: Fish Excretion versus External Loading. Can. J. Fish. Aquat. Sci., 47: 364-372.
Cahn, A. 1929. The Effect of Carp on a Small Lake: Carp as a Dominant. Ecology, 10: 271-274.
Drenner, R., J. Smith, S. Threlkeld. 1996. Lake Trophic State and the Limnological Effects of the Omnivorous Fish. Hydrobiologia, 319: 213-223.
Fletcher, A., A. Morison, D. Hume. 1985. Effects of Carp, -Cyprinus carpio L.-, on Communities of Aquatic Vegetation and Turbidity of Waterbodies in the Lower Goulburn River Basin. Aust. J. Mar. Freshw. Res., 36: 311-327.
Froese, R., D. Pauly. 2002. "Fishbase: Species summary for Cyprinus carpio" (On-line). Accessed 2 April 2002 at http://www.fishbase.org.
Lamarra, V. 1975. Digestive Activities of Carp as a Major Contributor to the Nutrient Loading of Lakes. Verh. Internat. Verein. Limnol., 19: 2461-2468.
Lammens, E., W. Hoogenboezem. 1991. Diets and Feeding Behavior. Pp. 353-376 in I Winfield, J Nelson, eds. Cyprinid Fishes. London: Chapman and Hall.
Lougheed, V., B. Crosbie, P. Chow-Fraser. 1998. Predictions on the Effect of Common Carp (-Cyprinus carpio-) Exclusion on Water Quality, Zooplankton, and Submergent Macrophytes in a Great Lakes Wetland. Can. J. Fish. Aquai. Sci, 55: 1189-1197.
McCrimmon, H. 1968. Carp in Canada. Fisheries Research Board of Canada.
Nelson, J. 1984. Fishes of the World. New York: John Wiley and Sons, 2nd ed..
Page, L., B. Burr. 1991. A Field Guide to Freshwater Fishes. Boston: Houghton Miflin.
Smith, R. 1991. Social Behaviour. Pp. 509-529 in I Winfield, J Nelson, eds. Cyprinid Fishes. London: Chapman and Hall.
Tomelleri, J., M. Eberle. 1990. Fishes of the Central United States. Lawrence, Kansas: University Press of Kansas.