The koi carp descends from the common carp, a large grouping of fish that are native to both Asia and Central Europe. Several different species of carp were originally kept in East Asia, where they were consumed as food.
During the 19th century, colorful common carp from wild ponds and lakes were domesticated within Japan, and selectively bred to produce the bright color and pattern variations that we are familiar with in the koi today.
Do koi carp still live in the wild today?
Common carp, the ancestors of our domesticated koi, can still be found living wild in various different countries, including Japan, where the koi carp originated.
Natural color mutations within wild carp populations still occur within the wild, and released koi can successfully breed back to a wild state within existing
common carp populations.
Where in the world can you find wild koi carp?
The koi carp is a coldwater fish that is very adaptable and capable of thriving within water of various different temperatures. This adaptability means that the koi can survive in the wild in many different environments.
Today, koi carp are present in the wild on every continent in the world, except for Antarctica. This wide distribution is due to koi being introduced into native carp populations by owners and breeders.
Are koi carp harmful to native wildlife?
In some countries and areas, wild and released koi carp are considered to be an invasive species, and they often interfere with natural ecosystems.
Koi contribute to the turbidity of water in still ponds and lakes, as they constantly stir up the substrate. This can cause the water to become mucky-looking and churned up, and make it difficult for aquatic plants to take root and thrive.
As well as upsetting the ecosystem of ponds and lakes for other fish and plants, wild koi can render the water undrinkable for both people and livestock.
This is due to the reduction in aeration of the water that comes from fewer established plants.
In Australia, the koi carp is regarded as a “noxious fish,” meaning that it has been declared harmful to the native wildlife. However, in North America, koi carp are often deliberately introduced into man-made ponds and lakes on golf courses. This keeps the spread of water-borne larvae and the level of plant growth under control.
Due to the potential impact on the natural ecosystem and as domesticated fish are unlikely to survive long in the wild, you should never release a domestic koi carp, regardless of where you live.