Kohaku Koi Care Guide
Kohaku is a white-bodied koi variety with red markings, a coldwater pond fish bred from Cyprinus carpio requiring a large outdoor pond.
Compiled by Aquairi from published sources · Published · Updated
Overview
Kohaku is a koi variety described as a white-skinned fish with large red markings on top; the name means "red and white". Koi are colored varieties of carp kept for decorative purposes in outdoor ponds and water gardens. Kohaku was one of the first ornamental varieties established in Japan.
Taxonomy
- Family: Cyprinidae
- Genus: Cyprinus
- Scientific name: Cyprinus carpio var. Kohaku
- Note: Kohaku is a selectively bred color variety of the domesticated carp Cyprinus carpio
History
Systematic breeding of ornamental carp began in Japan's Niigata Prefecture in the 1820s. Kohaku emerged as one of the earliest established ornamental varieties, with its modern form fixed in the late 19th century.
Pond requirements
- Minimum volume: 4000 L (1057 gal)
- Temperature: 4-26 °C (39-79 °F); benefit from a 15-25 °C range
- pH: 7.0-8.5
- GH: 8-20 °dGH
- Pond depth: at least 1 m, or 1.5 m in harsh winters
- Lifespan: 25-50 years
Diet
Koi are omnivorous and eat a wide variety of foods. The parent species Cyprinus carpio consumes benthic organisms and plant material in the wild. In ponds koi accept prepared foods as well as items such as peas, lettuce and watermelon.
Care notes
Koi are coldwater fish whose immune function becomes very weak below 10 °C. They reach a large adult size and produce a heavy bioload, so they require a spacious, well-filtered outdoor pond rather than an indoor aquarium. They are not suited to planted setups, as carp dig and consume vegetation.
Kohaku Koi Breeding Guide
Overview
Kohaku is a variety of koi (Cyprinus carpio): a white-skinned koi with large red markings on the top. Koi are large pond fish, so breeding is an outdoor pond project rather than an aquarium one. All koi varieties result from selective breeding, and the Kohaku pattern is fixed only by systematically culling undesirable offspring during development.
Conditioning
Koi benefit from being kept in the 15–25 °C (59–77 °F) range, and their immune systems are very weak below 10 °C (50 °F), so conditioning mature breeders in stable, warm-season water supports a healthy spawn.
Breeding Setup
Spawning is set up in a pond with a target for the sticky eggs to attach to. A sticky outer shell around each egg helps keep it in place so it does not float around, so spawning ropes, brushes or fine plants are provided as a receiving surface.
Spawning Behavior & Trigger
When koi naturally breed on their own they tend to spawn in the spring and summer seasons. The male starts following the female, swimming right behind her and nudging her. After the female releases her eggs they sink to the bottom of the pond and stay there, held in place by the sticky shell.
Egg & Fry Care
Koi produce thousands of eggs per spawning, though many of the fry do not survive due to being eaten by others. Because of the high losses, separating eggs or fry from the adults improves survival.
Common Challenges
Even from the best champion-grade koi, most offspring are not acceptable as nishikigoi — they may have no interesting colors or even be genetically defective — so expert culling is required. For Kohaku the goal is a clean white skin carrying a well-balanced red (hi) pattern.