Koi fish, belonging to CYPRINIDAE, is a large and precious fish for ornamental and edible purposes. It has a strong body, bright colors, bright stripes and elegant swimming style. It has the reputation of "a living gem in water", symbolizing auspiciousness, joy, prosperity and happiness. It is also called "good luck fish" and "feng shui fish". Koi fish originated in China, and its seed production was improved in Japan. After years of cross breeding, koi fish with systematic characteristics has been formed. At present, the domestic and international markets are promising, and breeding is getting hotter and hotter. Its cultivation techniques are as follows.

I. Construction of fish ponds

Choose humus soil, where the leeward is sunny and the water is rich (preferably spring water rich in mineral elements, which is beneficial to increase the pigment of fish body and make the color of koi fish body more bright and beautiful), and build the pond in a convenient place for irrigation and drainage. Domesticated koi fish can use courtyard space or roofs to build ponds. The parent fish pond covers an area of 30-40m2, the pond depth is 1.5m-2m, the water depth is 1.2m- 1.5m ... spawning pond 1.5-20 m2, the water depth is 1.5 m, and the water depth is/. The depth is 0.8m- 1m, the water depth is 0.6m-0.8m The nursery pond10-15m2, the water depth is 0.5-0.6m, and the water depth is 0.4m.. The area of the fish pond depends on the feeding amount, and the larger the area, the better. The depth of the pond is 1.5m-2m, and the water depth is 1.5m. It is best to build a cement pond, and the bottom layer is inclined to one end of the drainage ditch. Before the new cement pool is used, it should be dealkalized, filled with water, then added with rice straw or wheat straw, soaked for 15 days, then drained and washed with clear water for several times. Then add new water for later use.

Second, breeding and seed cultivation.

The breeding age of koi fish is 3- 10, and its weight is above 1.5 kg. Koi fish was selected as the parent fish because of its strong physique, glittering and translucent color, obvious species characteristics, stable swimming posture and no illness or injury. In May every year, when the water temperature is stable above 1.6 degrees Celsius, the female and male koi fish are picked out according to 1:3 and put into the spawning pond, and the disinfected fish nest is first placed on the top of the spawning pond. After spawning, the parent fish are fished out, and the fish nest is left in the pool to hatch. After 5-7 days, fry are hatched and cultivated. After 3-4 days of incubation, the fry began to float to the surface for food. At this time, the fry will be fished into the fry pond. Use cooked egg yolk, soybean milk, seaweed and soft worms as bait. After 1 week, feed Daphnia, red worm and chopped earthworm, and supplement artificial compound feed appropriately, once every morning and evening. When the fish grow to more than 2 cm, they are moved to adult fish ponds for feeding.

Three. Feeding and management of adult fish

For large-scale cement pond culture, the stocking density should be 1 ~ 3 per square meter of water surface, and grass carp, silver carp and bighead carp can be mixed appropriately. In courtyards and hotels, ponds can be built for direct viewing. The depth of the pond should be 0.6-0.8 meters, and the density can be slightly higher if it is raised alone, and 3-5 animals can be raised per square meter. The pool is equipped with water spraying facilities or circulating micro-water conditions, and it is usually fed twice a day. It can be fed with special brightening materials and culture materials for raising ornamental fish to promote its color and form a perfect body shape. Koi fish is an omnivorous fish. Leftovers, peels, etc. It can be mixed with 10% animal feed such as viscera, snails, maggots, pupae and earthworms to make granular feed. The contents of crude white matter and crude fat in diet should reach 35% and 5-8% respectively. Adhere to the "four fixed" feeding, feeding 1 time every morning and evening. The feeding amount depends on the water temperature, weather changes and the fish's feeding situation, which is about 2- 10% of the total weight of the fish, and it is appropriate to eat it within 10-20 minutes.

Adhere to daily inspections and fish out the remaining bait residues in time. Change water every 2-3 days in summer 1 time. Change water every 4-5 days in spring and autumn 1 time, and the water change rate is 1/3- 1/2 of the original pool. Keep the water fresh. Pay attention to increasing oxygen in hot and rainy weather to prevent flooding. In winter, koi fish can be moved indoors, the water temperature should be kept at 2- 10℃, and digestible bait should be properly fed to facilitate overwintering.