Common Names: Domestic Koi, carp, common carp, European carp, koi, nishikigoi
Type Locality: Europe; aquacultured and feral populations appear to derive from a population in the Danube
Range: Originally Eurasia, but now established globally. It is a major ecological threat in many places; aside from the competitive edge this species has due to its toughness and adaptability, its mud-sifting feeding habit causes severe turbidity, which often h
Taxonomic Troubles: Although there has been some controversy regarding subspecies, this is the original binomial. Carp will hybridize with several other cyprinids, including goldfish Carassius auratus--the source for the long fins of the so-called "butterfly koi." Genetic
Size: 120 cm (4 feet)
Preferred Water Chemistry: Temperate, 3 to 32 degrees Celsius (37 to 90 degrees Fahrenheit). Can tolerate brackish conditions and low oxygen saturations.
Difficulty: One of the hardiest fish known. May live 100 years or more.
Tank Setup: This is not an aquarium fish. It is ideal for medium to large ponds and for lakes.
Feeding: Fully omnivorous. Eats invertebrates, fish, plants, seeds, plankton, algae, detritus, sewage, garbage, etc.
Breeding: From a few thousand to half-a-million eggs, are deposited by each breeding female in flooded grassy areas when the awater warms in the spring. At spawning time, males develop small white breeding tubercles, especially on the head and fins. Several males chase a female, which stimulates her to deposit her eggs in the vegetation. Fry hatch in about three days. Due to the huge number of fry and their extreme variability, ruthless culling is necessary to preserve and improve the strain.
A large-scaled, stocky fish with two barbels. Although gold or greenish brown and grey are the natural coloration, koi have been developed in a number of brilliant colors and patterns. Specific colors and combinations of colors define the various recognized varieties.
So common that it is often considered a trash fish, ironically the carp Cyprinus carpio is also the source species for domesticated koi, of which some show specimens command prices of millions of dollars apiece. Although the domestication of carp may be as old as 4000 years, the colored variants we recognize today as koi were developed a couple of centuries ago in Japan.
In the last century, koi breeding has gained rapidly in popularity around the world, though Japanese breeders still retain prominence. This species is also a popular food fish in several cultures. Koi are bred to look best viewed from above, so a garden pond is an ideal way to display them. Small ponds, however, including any pond less than 4 feet deep, should house goldfish rather than koi.
Koi are large, thick-bodied, heavy-feeding waste producers, and they deserve adequate swimming room and clean water conditions. The resultant high bioload makes it necessary in almost any koi pond to utilize a UV sterilizer to prevent a profusion of free algae and pea-soup conditions. Whether viewed as gefilte fish, invading exotic, or prize-winning ornamental, the carp is one of humanoid's closest associates.