How to identify high quality fish species

"half the profit is good for planting, and half the grain is good for seedlings." Strong and good quality fish species is not only an important factor to improve the survival rate of fish species, but also an important basis and guarantee to increase fish production and economic benefits. High-quality fish species should have: appropriate specifications, neat, robust and harmless, lively action, strong food grabbing power, specifically to identify high-quality fish species can be summarized as "three look and one sampling". A look: the specifications of the same fish species in the same pond should be neat and uniform, with little difference in body length and weight, but on the contrary, there is a large individual gap and uneven inferior fish species, due to predation, mixed germplasm, poor feeding and other reasons, often the overall survival rate of this inferior fish species is very low. Second, the body color of high-quality fish is bright and glossy, and different species and different feeding methods have different body color. generally speaking, the back of high-quality silver carp should be silver gray, the side and abdomen of silver carp should be silver-white; the body color of high-quality grass carp is light golden yellow, and the grayish-black reticulated scales are more obvious, and the stronger the fish is, the more obvious the light golden yellow is. The body color of high-quality bighead carp is mostly light golden yellow, and the black markings are not very obvious. If the fish is dark or even black, it means that the fish is weak or diseased. The gloss of the body surface of the fish is caused by the mucus layer covered by the body surface of the fish, which is rich in protease and lysozyme and can protect the scales and skin of the fish from diseases and insect pests. Fish or weak seedlings lack a mucus layer and have no luster on their body surface. of course, fish species will also secrete a large amount of mucus and lose their luster when they are attacked by external diseases and insect pests. For example, when fish are attacked by small melons and insects, their body surface will be covered with a thick layer of mucus, which is a stress response of fish species to external attacks. Three look: the activities of high-quality fish species are lively and clustered, and when they are frightened, they quickly dive into the bottom of the water in groups, with strong grabbing power and strong reverse water, and when the fish are dense, they can only see the fanning of their tails constantly; while the weak fry or sick fish with poor physique move slowly, do not cluster, swim alone, the grabbing power is weak, and the reverse water is poor. One sampling: the fish that are randomly selected to check their advantages and disadvantages and high quality beat violently when leaving the water, the individual is fat, the head is small and the back is thick, the body color is smooth, the muscle is moist, the scales and fins are intact, the Gill cover is not open, the tail is not bent, there are no parasites and scars on the body surface, and the body shape is normal and without deformities. On the contrary, weak fry or diseased fish with weak activity, incomplete scales and fins, hyperemia, thin fish body, large head and small tail, thin back like blade, or even "no belly" or "sticky net" are regarded as inferior seedlings.