Koi care guide
Cyprinus rubrofuscus (Cyprinus carpio) · Cyprinidae
Koi (Cyprinus rubrofuscus (Cyprinus carpio)) is an aquarium animal. It belongs to the Cyprinidae family. It is native to Ornamental carp kept in outdoor ponds and water gardens; Japanese sites hold carp remains from the Jomon period.. Water temperature: 15°C – 25°C. pH: 6.5 – 9.0. Care difficulty: Moderate to demanding.
How do you care for Koi?
| Temperature | 15°C – 25°C |
|---|---|
| pH | 6.5 – 9.0 |
| Placement | A coldwater fish for an outdoor pond; ponds are usually a metre or more deep where summers are warm, with a pump and filter to keep the water clear. Not suited to an ordinary indoor glass tank. |
| Growth | Grows large; reported lifespans range from a little over 50 years to 100–200 years. |
| Difficulty | Moderate to demanding (needs a big pond, strong filtration and seasonal management) |
| Family | Cyprinidae |
How do you trim and propagate Koi?
Do not feed when the water drops below 10 °C. On arrival, float the bag in the pond or a quarantine tank until the temperatures equalise, then add pond water gradually; discard the transport water.
What problems affect Koi?
The immune system is very weak below 10 °C. Viral diseases such as KHV (koi herpesvirus) and spring viraemia have forced whole farms to be depopulated.
How do you fix Koi problems?
Keep temperatures in the 15–25 °C range where possible; quarantine new fish; a KHV vaccine exists (Wikipedia cites about 90% success).
Where does Koi come from?
Ornamental carp kept in outdoor ponds and water gardens; Japanese sites hold carp remains from the Jomon period. · Biotope regions: East Asia.
What should you know before buying Koi?
Needs a pond with deep areas and cover from herons and mammals. Never release koi into the wild.
Sources
- Koi — Wikipedia
- Cyprinus carpio — FishBase
Care details checked against these sources on 2026-10-29.
See Koi in a living world
- Koi Courtyard — aquarium
Last updated · Open the interactive 3D guide · All species care guides