Sharing Experience on Artificial Breeding in Koi Culture

1. Artificial induced spawning of koi. The time for artificial induced spawning of koi is generally chosen when the water temperature is around 25°C. The two-injection pectoral fin method can be used; effective drugs for inducing estrus include human chorionic gonadotropin, luteinizing hormone-releasing hormone analogue, and domperidone, etc.

2. Artificial insemination. In the breeding season, place the female and male parent fish that are about to spawn together in one pond, put in an appropriate amount of spawning nests, add some new water, and then observe carefully. When the male fish is found chasing the female fish vigorously, it indicates that spawning and sperm release are imminent. At this time, scoop up the female and male parent fish together with the water using a washbasin, place them separately into white enamel trays, and gently press the abdomen of the female and male parent fish. If mature eggs or milky white semen flow out from the genital pores respectively, it indicates that they have matured. After the female and male parent fish are ready, artificial insemination can be carried out. First take the female fish, wipe the fish body dry with a towel or gauze; one person gently holds its caudal peduncle with the left hand so that it cannot swing left and right, and gently holds the fish head with the right hand; another person uses the right thumb to gently press the abdomen of the female fish from the front end of the ovary at the pectoral fin, and eggs will flow from the genital pore into a previously disinfected and cleaned white enamel basin. Squeeze continuously several times until it is basically emptied. Then handle the male fish in the same way, quickly squeeze the semen into the basin containing the eggs, and add a certain amount of isothermal new water. Then use a clean feather to gently mix the sperm and eggs evenly, fully mixing them for rapid insemination. 3. Hatching. Disinfect and clean the hatching container, and fill it with hatching water, that is, unpolluted river water, well water, tap water, etc. free of pests. When the water temperature is close to the spawning water temperature, put in the disinfected spawning nests. Generally, the water depth is 25-30 cm, with 6-8 spawning nests per square meter; if the hatched fry are to be reared in this container during the stage before becoming juvenile fish, the density of spawning nests should be reduced to 3-5. The length of hatching time is closely related to water temperature: at a water temperature of 18°C, it takes 5-7 days; at a water temperature of 22°C, it takes 3-4 days; at a water temperature of 25%, it takes 2-3 days. The water temperature is generally controlled within the optimal range of 18-24°C, and the hatching time is controlled at 3-4 days. The hatching rate is as high as over 90%, the hatched fry have the best physique, and the number of high-quality fish is the largest.