Skills of selecting juvenile fish in brocade carp culture

After hatching, the brocade carp larvae have been raised for about 20 days to 1 month, and when the fish grows to about 3 cm, it is necessary to select. The purpose of selection is to eliminate the inferior and retain the superior, strengthen the growth rate, and achieve the effect of protecting genetic traits. Therefore, the selection of young fish is the most important link to obtain high quality koi in the breeding process. Generally speaking, the selection work is carried out three or four times during the period of more than 3 months after hatching. The time of selection varies depending on the variety, the speed of growth and the time when the markings appear.

For example, Zhaohe tricolor koi can be selected after hatching for more than two weeks; gold system koi can be selected for 50 days; and red and white and Dazheng tricolor koi can be selected for about 60 days. In short, the selection of young fish can only begin when they grow to a length of 3 to 5 centimeters. The main point of the selection is: first, get rid of the deformed, not brightly colored fish. It should also be selected according to the growth status and quality of the pattern, such as red and white koi, those with light red markings should be eliminated, and those of gold koi with no gloss on the head, poor scale coverage, many fish spots, and poor growth of pectoral fins should be eliminated.

The elimination rate of koi is relatively high in the process of feeding. If a parent fish usually lays 200000-400000 eggs, after several times of selection after hatching, only about 5000 large fish are left. According to relevant data, the parent fish laid 100000 eggs, and 60, 000 to 70, 000 larvae were obtained after 4-5 days of hatching; 30, 000 young fish with a body length of 2 cm were obtained after 20 days of feeding; by the first selection in July, only 16000 were left; after the second selection or daily feeding, only 5470 fish were left, and only 3600 fish were left when they overwintered in November. At the end of one year, only 2300 strong fish were left. It can be seen that the elimination rate is so high that it can be said to be "one in a million".