Breeding technique of koi

Because of their large size, koi usually breed in ponds. Brocade carp egg band sticky, fertilized eggs adhere to water plants and other attachments to develop, so artificial fish nests must be placed in the pool where brocade carps are bred. In order to increase production, artificial reproduction can be carried out to cultivate fish fry.

It is relatively easy to distinguish between male and female, from the body shape, such as abdominal hypertrophy for female fish, thin elderly for male fish; from the anal point of view, female anus is wide and flat, male anus is small, concave. In the stage of sexual maturity, you can check whether there is a "chasing star" on the edge of the pectoral fin, and touch the fin with your hand. If there is a rough horny protuberance, it is a male and a smooth one is a female. Mature male fish gently press on the abdomen and white semen flows out.

The selection of parent fish in artificial reproduction requires obvious species characteristics, good color, markings, background color and posture, healthy and lively, and large and plump female fish. The ratio of 1 female to 2 male can be used to improve the fertilization rate of parent fish for reproduction. Although the 1-year-old koi has matured, it is best to choose 3-5-year-old parent fish in order to ensure quality. If the age of parent fish is too old, the hatching rate of fertilized eggs will decrease. Before breeding, the female and male fish are raised separately, and then put back into the spawning pond when breeding. Spawning pool can be used soil pool, cement pool, the area of about 20 square meters is better, the pool water depth of about 1 meter is appropriate, can be determined according to the conditions. Disinfect the spawning pool 3 days before spawning. One day before spawning, put it in the fish nest. When the water temperature is above 18 ℃, koi can spawn and fertilize naturally. After spawning, take out the fish nest, disinfect it, and put it into the incubator.

The second pectoral fin injection method can also be used to induce labor. The dose of luteinizing hormone-releasing hormone analogue was 12 μ g per kilogram for females and halved for males. The dose of the first injection was 1 stroke 3 of the total dose, and the injection margin of the second injection was 8 hours. After the injection, the parent fish is placed in the spawning pond and a row of fish nests are hung in the pond. About 10 hours later, eggs can be found at the mouth of the nest, and artificial insemination is used immediately. One person carries a bowl or basin, and one person grabs the female fish and squeezes the eggs into the bowl or basin. Quickly squeeze semen into a bowl or basin containing eggs. If there is too little semen, add an appropriate amount of saline, stir with feathers for 1 minute, and sprinkle evenly on the net cloth with fish nests in the cage. During the incubation period, it is required to use pollution-free fresh water, sufficient dissolved oxygen and pH 7-8. During the incubation period, water mildew is mainly prevented. Generally, 15-20ppm malachite green solution is sprinkled into the cage every day. Fish fry cultivation rotifer was used as the opening bait for fish fry. One week later, the fish fry were fed with artificial feed, and one month later, all the rotifers were fed with artificial feed.