What are the key points of brocade carp fry and fingerling cultivation?

Brocade carp hatched for 3-4 days, the yolk sac was absorbed and exogenous nutrition began. If the natural bait is insufficient, feed cooked egg yolk juice or rotifer and improve the water quality. After 7 or 8 days, switch to larger foods, such as Cladocera, surimi or pellet bait. When the larvae are reared for 20 to 30 days and the body length reaches 3 cm, they should be selected (screened) to get rid of the inferior and retain the good, and to maintain the good characters of the germplasm. The selection work was carried out 3 or 4 times within more than 3 months after hatching. The selection varies slightly depending on the variety, the growth rate and the time of appearance of markings. For example, Zhaohe tricolor koi began to be selected more than 2 weeks after hatching, gold system koi began to be selected in 50 days, and red and white and Dazheng tricolor systems began to be selected in about 60 days. When selecting, first remove the deformed, not brightly colored fish, but also according to the growth status and quality standards of the pattern. Red and white koi should eliminate individuals with light red markings. The individuals with dull head, poor scale coverage, many miscellaneous spots and poor growth of pectoral fins of golden koi should be eliminated. The elimination rate of koi is very high in the process of raising. For example, the parent fish laid 100000 eggs and got 60, 000 to 70, 000 larvae. There were still 30, 000 when they were cultivated into summer flowers. After the first selection, 16000 were left, and only about 3, 600 were left when they overwintered in autumn.

After the first selection, the young fish left behind can be placed in a fish pond with an area of 5 meters × 5 meters, with a water depth of 30 to 50 centimeters and a density of 120 to 150 fish per meter. no, no, no. The stocking density of the fish left after the second selection is 90,120 fish / m. From now on, it becomes more and more sparse. When the length of fish reaches 10 cm to 20 cm, the stocking density should be comprehensively considered according to the size of water body, water quality, equipment conditions and culture technology. The selected koi can be fed with bean cake, rapeseed cake, pellet bait, or bait such as water earthworms, molluscs, duckweed and so on. The feeding rate is 10% to 30% of the fish body weight. And often change water and clean up.