It is fastidious to cast fish in early spring.

The quality of fish species of the same age requires the same specifications, similar body length and weight, thick back muscles, bright color, intact scales and fins, normal activity, strong traceability, Gill cover not stretched in the basin after leaving the water, the tail does not bend, beating more than, there are no scars and parasites on the body surface.

Fish species disinfection some farmers do not disinfect fish seeds at all, resulting in high incidence, and the effect of drug control is not ideal. in fact, as long as we do a good job in disinfection of fish species, we can often get twice the result with half the effort in the prevention of fish diseases. Fish seed disinfection should pay attention to the following three points: first, medicine should be used now, dispensing should use clear water, avoid using fat water, and avoid direct sunlight when washing fish seed. Second, the drug dose should be accurate to avoid insufficient or overdose. Third, the soaking time should be appropriate. When it is found that the fish can not stand the phenomenon, you should immediately add water or put the fish into another appliance.

The method and time of release must first be strictly checked whether the effect of the pond cleaning drug has passed before the fish goes into the pond. Methods: put a small cage in the fish pond that is about to be released, in which dozens of fish are tested and observed overnight to see if their activities and floating heads are abnormal, such as restlessness, floating head struggle, swimming around, and so on. It shows that the medicine for clearing the pond still has residues and shall not be released immediately, and the fish can only be released after the drug has completely disappeared. In addition, before the fish species enter the pond, the whole pond must be netted once or twice with a dense eye net to remove harmful insects, frog eggs and wild miscellaneous fish from the pond, so as to ensure the safety of the fish species in the pond. It is best to choose to release the fish at noon on a continuous sunny day, when the fish adapt the fastest and the survival rate is the highest. In windy weather, fish species should be released in the upwind of the fish pond, so as to avoid being blown to the edge of the pond in the downwind.

Pay attention to the temperature difference between the fish species in the pond and the temperature difference between the water temperature in the pond and that in the pond should not exceed 3 ℃. If the temperature difference is too large, the water temperature in the container should be adjusted to make it close to the pool water temperature. Fish species transported with oxygen in plastic bags should be treated by "slow fry" when they go into the pond. The fish species should also be counted accurately when they go into the pond.