How to identify high-quality fish fry? Just look at these few points

First, look at the size of the fry. In the same pond, the same species of fish should be uniform and even when harvested, with little difference in body length and body weight. On the contrary, poor-quality fry with large individual differences and uneven size often have a very low overall survival rate due to competition for food, mixed genetics, poor rearing, and other reasons. Second, look at the body color of the fry. High-quality fry have bright, glossy body colors. Different species and different rearing methods produce fry with different body colors. Generally speaking, high-quality silver carp fry should have a silver-gray back, with silvery-white sides and belly; high-quality grass carp fry are pale golden yellow, with relatively obvious gray-black net-like scales, and the stronger the fish, the more obvious the pale golden yellow; high-quality bighead carp fry are mostly pale golden yellow, with black markings over the whole body not very obvious. If the fry's body color is darker, even blackish, it indicates that the fry are weak fry or sick fish; the gloss on the body surface of the fry is caused by the mucus layer covering the body surface, which is rich in protease, lysozyme, and others, and has the effect of protecting the scales and keeping the skin from being attacked by disease and pests. It is the first barrier for the fish itself against disease. Sick fish or weak fry lack a mucus layer, and their body surface has no gloss. Of course, when fry are attacked by external diseases and pests, they will also secrete large amounts of mucus and lose their gloss. For example, when fish are attacked by Ichthyophthirius multifiliis, the body surface is covered with a thick layer of mucus, which is a stress response made by the fry to external attack. Third, look at the activity of the fry. High-quality fry are lively in movement, strongly gregarious, and when startled quickly gather and dive to the bottom in schools; they have strong food-grabbing ability and strong upstream-swimming ability. When dense, the fry heads point downward, and only the tails can be seen constantly swinging, while weak fry or sick fish with poorer constitution move slowly, do not school, swim alone, have weak food-grabbing ability, and poor upstream-swimming ability. Fourth, sample randomly. Randomly take fry to check their quality. High-quality fry jump violently when out of water, are plump and strong, with small heads and thick backs, glossy body color, moist muscle, intact scales and fin rays, gill covers not open, tails not bent, no parasites or wounds on the body surface, and normal body shape without deformities. On the contrary, weak fry or sick fish jump weakly, have incomplete scales and fin rays, congestion, thin and weak bodies, large heads and small tails, backs as thin as a knife edge, and even "no belly," "sticking to the net," and so on.