How to identify the quality of fish species in aquaculture

Strong fish species is not only an important basis for increasing adult fish production, but also one of the main conditions to improve the survival rate of fish species. There are 5 main criteria for identifying the quality of fish species, which can be summarized as "four-look-one sampling".

As soon as we can see whether the specifications of the pond are uniform and the same species of fish, those who come out of the pond with uniform specifications have a relatively strong physique. However, if there is a large individual gap, the survival rate of the group is often lower.

Second, look at the body color of the fish species, which may reflect the physical fitness of the fish species. Different fish species have different body colors. Generally speaking, the body color of high-quality grass carp is light golden yellow, and the gray-black reticulate scales are more obvious. The stronger the fish, the more prominent the light golden color. The body color of high-quality green fish is bluish gray and white. the stronger the fish is, the lighter the body color is. The back of high-quality silver carp is silver-gray, and the sides of the body and abdomen are silver-white. The body of high-quality bighead carp is mostly light golden yellow, and the black markings are not obvious. If the fish body color is dark, or black, it means that these fish are thin or sick fish.

Third, see if there is a gloss on the body surface. The body surface of the strong fish is a thin layer of mucus, which is used to protect the scales and skin from the invasion of bacteria, so the body surface shows a certain luster. On the other hand, the sick and injured fish lack mucus and have no luster on the body surface. Some diseased fish have too much mucus on their body surface and lose their luster.

Fourth, look at the activity of the fish species. The strong fish species swim lively and have strong reverse water. When the fish is dense in the cage or running water, the fish species are head down, and only the fish tail is constantly flapping. And those species that swim slowly and have poor reverse current belong to the sick and weak species.

A sampling is a sampling inspection of the growth of fish species, the growth of fish length and weight, in general, is corresponding to each other. However, although the body length of the same kind of fish is the same under different feeding conditions, the weight may be slightly different, especially in the species that lose weight after lack of food or illness. Therefore, the quality of fish species can be identified according to the relationship between body length and weight. Take silver carp and grass carp as examples, there are 37 high-quality fish species with a body length of 8 cm, 25 fish per kilogram with a body length of 10 cm, 10 fish with a body length of 13 cm, and 5 fish with a body length of 17 cm. Generally speaking, the proportion of body length and weight in line with the above criteria are high-quality fish species, otherwise they are inferior fish species.