All fish / Cyprinidae

Koi

Cyprinus carpio

Also known as common carp, koi carp, nishikigoi, mirror carp, leather carp, butterfly koi, fancy carp, european carp, coi, ปลาคาร์พ, ปลาไน, ikan kap

Koi are coloured, domesticated forms of the common carp, bred in Japan in patterns of red, white, black, yellow and metallic shades. They are kept as long-lived, tame pond fish that learn to take food from the hand, and well-known varieties include Kohaku, Sanke and Showa.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

60 cm

Temperature

4 to 28 °C

pH

7 to 8.5

Smallest tank

4000 litres

Keep as

Group of 3 or more in a pond

Diet

Omnivore: koi pellets, wheatgerm food in cool weather, vegetables, worms and insects

Swims

Bottom of the tank

Lifespan

25 to 35 years

Water

Freshwater

Wild range

Eastern Europe and Asia (Danube, Black, Caspian and Aral Sea basins to China); introduced worldwide

Breeding

Koi scatter sticky eggs over plants or spawning mats in late spring once the water warms, and they often spawn in garden ponds without help. Producing high-grade fish is harder, because breeders have to cull heavily from very large numbers of fry.

Good to know

Koi grow far too large for home aquariums and need a big, well-filtered pond. Common carp are invasive in many countries, so never release them, and check local rules because koi herpesvirus (KHV) and spring viraemia of carp are notifiable diseases in some places.