Asagi Koi Care Guide
Asagi is one of the original koi varieties of Cyprinus carpio, recognised by a blue-grey netted back and red markings on the flanks and cheeks.
Compiled by Aquairi from published sources · Published · Updated
Overview
Asagi is an ornamental colour variety of the common carp, Cyprinus carpio, developed in Japan. It is recognised by a light blue to blue-grey net-like pattern over the back, with red (and occasionally pale yellow or cream) colouration below the lateral line and on the cheeks. Asagi is one of the original koi varieties and played a foundational role in the development of other strains.
Taxonomy
- Family: Cyprinidae
- Genus: Cyprinus
- Scientific name: Cyprinus carpio var. Asagi
- Type: ornamental colour variety (Nishikigoi) of the common carp
History
Systematic ornamental carp breeding began in the 1820s in the Nijumurago region of Niigata Prefecture, Japan, the hub from which most other Nishikigoi varieties were later bred. Records from 1843 mention Asagi among the coloured carp varieties of the period. The Asagi line was also used to create the Shusui variety in 1906 by crossing it with a German leather carp.
Pond requirements
- Minimum volume: 4000 L (pond, not aquarium)
- Temperature: 4-26 °C (39-79 °F); thrives around 15-25 °C
- pH: 7.0-8.5
- GH: 8-20 °dGH
- Lifespan: 25-50 years
- Pond depth: 1 m or more, with 1.5 m for harsh winters
Diet
Koi are omnivores and, as with the parent species Cyprinus carpio (trophic level about 3.1), feed on a wide variety of foods, including benthic organisms and plant material. In ponds they accept varied foods such as peas, lettuce and watermelon in addition to prepared diets. Feeding should stop when water temperature drops below about 10 °C, as the immune system becomes very weak in cold water.
Tank requirements
Asagi koi grow large (roughly 60-90 cm) and are pond fish rather than aquarium fish; the common carp can reach up to 120 cm and a reported maximum age of 38 years in the wild form. They require spacious ponds with strong filtration and are not suitable for typical indoor aquariums.
Conservation status
The parent species Cyprinus carpio is listed as Least Concern on the IUCN Red List (assessed 2022). Asagi is a domesticated ornamental variety and is not assessed separately.
Asagi Koi Breeding Guide
Overview
Asagi is a variety of koi (Cyprinus carpio): light blue above and usually red below, and one of the original koi varieties. 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 Asagi 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 Asagi the goal is an even, light blue scaled back over red on the flanks.
Bekko Koi Breeding Guide
Overview
Bekko is a variety of koi (Cyprinus carpio): a white-, red-, or yellow-skinned koi with black markings. 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 Bekko 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 Bekko the goal is a clean solid base colour carrying neat black (sumi) markings.
Butterfly Koi Breeding Guide
Overview
Butterfly koi (Cyprinus carpio) are a hybrid of koi and Asian carp with long flowing fins, developed in the 1980s. Koi are large pond fish, so breeding is an outdoor pond project rather than an aquarium one. The long-fin trait results from selective breeding, and is maintained only by systematically culling offspring that do not develop the trailing fins.
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 Butterfly koi, breeders select for long, evenly developed, undamaged trailing fins in addition to colour.
Doitsu Koi Breeding Guide
Overview
Doitsu refers to scaleless koi (Cyprinus carpio) derived from the German carp lineage; the colour patterns can vary. 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 scaleless Doitsu trait is maintained only by systematically culling offspring that do not show it 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 Doitsu the goal is a clean scaleless skin (apart from the orderly dorsal and lateral scale rows of the German-carp line) carrying the intended colour.
Breeding Ginrin Koi
Overview
Ginrin Koi (Cyprinus carpio var. Ginrin) is a koi line distinguished by sparkling, metallic-reflective scales that overlay any colour pattern; Ginrin versions exist for almost all other koi varieties. As with koi generally, breeding is a pond-based, egg-scattering process. Koi naturally breed in spring and summer.
Conditioning
Koi spawn as the water warms into spring and summer, so breeding stock are typically held in the pond through the warming season. Koi do best when kept in the 15-25 degrees C (59-77 degrees F) range; their immune systems weaken below 10 degrees C, so robust, well-fed parents in good condition are the starting point.
Spawning Behavior & Trigger
Spawning is triggered by rising spring water temperatures. The male begins following the female closely, swimming right behind her and nudging her. The female then releases her eggs, which the male fertilises as they are scattered. Koi produce thousands of offspring from a single spawning.
Egg & Fry Care
After release, the eggs sink to the bottom of the pond and stay there; a sticky outer shell around each egg helps keep it in place. Many of the fry do not survive because they are eaten by other fish, so eggs and fry are best protected from adults. Nurturing the resulting fry is a tricky and tedious job usually done only by professionals.
Common Challenges
Even from the best champion-grade parents, the large majority of offspring are not acceptable for retention, so heavy selection (culling) is required. Predation on eggs and fry within the pond further reduces yield, making fry rearing the most demanding part of the process.
Sanke Koi Breeding Guide
Overview
Sanke (Taisho Sanke) is a variety of koi (Cyprinus carpio): similar to the Kohaku with the addition of small black markings, making it a classic three-colour koi. 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 Sanke 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 Sanke the goal is a white body carrying balanced red (hi) and small black (sumi) markings.