Breeding techniques of Carp Koi

1. Choose parent fish, and brocade carp, as ornamental fish, should select parent fish purposefully. Koi mainly watch the back, so it is best to choose the upper and lower flat, the profile is flat oval, the whole is spindle-shaped, and the color is based on the breeding purpose to select the corresponding body color of the parent fish.

2. Prepare the spawning pool, and generally use the small cement pool as the spawning pool. The shape of the pool is unlimited, the size is 4 meters high, 4 meters wide, 0.8 meters deep, and the water depth is 0.4 to 0.5 meters. The PH value of breeding water is 7.2-7.4, the water quality with brackish and low hardness is good, and the dissolved oxygen in the water should be above 4 mg / L. Pay attention to pond disinfection and pre-made fish nests in advance into the pond, fish nests are generally made of steaming and soaking foxtail algae or brown bark, tied into small bunches.

3. Spawning. In the northern part of China, the breeding season of koi is from late April to mid-June. When the water temperature rises to 16 ℃, the selected parent fish can be moved into the spawning pond, and 2-3 groups of parent fish can be put in each pond. When the parent fish are found to chase each other, it indicates that they are about to spawn. Spawning usually begins around 4 o'clock in the morning and ends around 10 a.m. Generally, 200000-400000 eggs can be produced at a time. Koi eggs are generally 2.1 to 2.6 mm in diameter. After giving birth, the eggs are swollen by water absorption and raised outside the egg membrane. Stickiness will adhere to the fish nest and hatch. After the parent fish have finished spawning, take out the nest with fertilized eggs, soak in 5%-7% salt water for 5 minutes and disinfect, then remove the new fish and hatch in the spawning pond.

4. Hatching; the water depth when hatching is generally 30 cm, and the requirements of water quality and water temperature are the same as those used when spawning. The incubation time is directly related to the water temperature, and shortens with the increase of water temperature in the range of suitable water temperature. 4 ℃ at about 18 ℃, 4 days at 20 ℃-22 ℃, and about 3 days at 25 ℃. The newly hatched larvae do not move or eat, and rely on the absorption of the yolk sac in the abdomen. after the yolk is absorbed, the larvae begin to swim freely and open their mouth to feed outside food. bait should be given in time.

5. The cultivation of fish fry; the process of fish fry cultivation is also a process of selecting the good and eliminating the bad, and it is a process of selecting and cultivating many times. The selection process is usually carried out for 3 times within 3 months after hatching. The first selection: within 30 days after hatching, when the fish grows to about 3 centimeters. The main purpose is to select individuals with strong physique, lively swimming and obvious breed characteristics, which can be eliminated for other individuals, or cultivated and sold separately. However, due to different varieties, the growth rate and the time of speckle formation are also different. For example, the selection of Zhaohe tricolor brocade carp begins about 15 days after hatching, the golden carp begins about 50 days after hatching, and the red-and-white series and Dazheng tricolor series begin about 60 days after hatching. Second selection: start about 20 days after the first selection. The selection criteria are whether the fin shape is good or bad, whether the color is bright or not, whether the pattern pattern is clear, whether the variety characteristic is obvious, and so on. Since then, the third or fourth selection is basically the same as the second selection.