Koi
Cyprinus rubrofuscus
FishFreshwater
- Care level
- Moderate
- Temperament
- Peaceful
- Minimum tank
- 1,000 L
- Maximum size
- 80 cm
- Temperature
- 10–26 °C
- pH
- 7–8.5
- Diet
- Omnivore
Care at a glance
Koi are not aquarium fish but pond animals, and that is the first thing to know. A full-grown koi easily reaches seventy to eighty centimetres and can outlive most pets — fifty years is not exceptional. Young koi in an indoor tank is a stopgap, not a destination.
In the pond it is all about filter capacity and oxygen: koi produce a lot of waste and are sensitive to nitrite. They eat virtually every water plant and uproot the rest, so a planted pond and koi go badly together. They handle northern winters fine as long as the water is deep enough and a hole is kept open in the ice; through those cold months you do not feed.
Good to know
Related species
Values are mainstream hobbyist guidance, not gospel — always watch what your own animals need.
In the BlubHub app you link your inhabitants to this database and see the care info next to your own water parameters.