Spawning decides the quality of Nishikigoi~from late May to late June~
Hajime Isa

Spawning is the most important task in the year for us breeders. It requires a lot of delicacy, and there is no excuse for failure. All fine-quality Koi come from fine-quality oyagoi (parent Koi), so we are always looking for high-quality oyagoi and thinking about the combination of them. Spawning, which decides the quality of Koi, is the chance to show the breeder’s skills.

Quality and body conformation are the key to selecting an oyagoi with the necessary qualities for spawning. To own an oyagoi possessing good shiroji, sumi, hi and body conformation, we will travel no matter how far upon hearing about such Koi. Fortunately, since Niigata is the birthplace of Nishikigoi, many breeders have good oyagoi which makes it fairly easy to supply them. Good oyagoi produces good Koi. This virtuous cycle is the advantage of Niigata being the origin of Nishikigoi and one of the reasons Nishikigoi produced here are high in quality.

However, just because you obtain a good oyagoi does not necessarily mean you can produce good Koi. You must think about the genealogy and compatibility of the oyagoi, not just about their quality. The combination of oyagoi decides the quality of the offspring, so the key to spawning is the mating of oyagoi. You constantly have to keep in mind which Koi goes together with which Koi. You go to Koi shows forming images of combinations by checking out each Koi. When you find a Koi you want, you ask the owner or breeder the Koi’s genealogy because inbreed results in the birth of weak Koi. The selection and combination of oyagoi require a lot of attention and know-how.

Spawning season depends on the climate of each region, but in Niigata, it takes place from late May to late June when the water temperature is about 20 C (68 F) degrees. There are two spawning methods: natural spawning and artificial spawning. Natural spawning is putting one female Koi and two to three male Koi in one pond for the female to spawn on the kinran (waterweed-like synthetic fiber for attachment of the eggs). We use several males to increase fertility, but the problem is that we do not know with which male the female Koi mated. Using one male is OK, but it is inefficient considering the hatching rate and labor hours. In artificial spawning, the breeders anesthetize the female Koi in travail and male Koi, take out the eggs, and mix them with the sperms. Then they attach the eggs to the kinran which makes it possible for the breeders themselves to decide the pairing of the egg and sperm, the advantage being that it is clear which male was bred with which female. That’s why I employ the artificial method. However, the smallest mistake can result in the loss of all eggs and sperms, so extreme care is necessary.

Producing high-quality Koi is not easy even for us breeders, so I believe it might be quite difficult for Koi lovers. However, crossing your own Koi and raising their offspring bring you a new world of pleasure and a chance to learn more about Koi, so if you have the opportunity, you should definitely learn the process of artificial spawning and try it.

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The life of Nishikigoi
  1) Spawning
  2)  Kuroko selection and sorting
Koi Disease
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