Releasing fish fry in early spring requires care; keep these precautions in mind

Fish fry quality For fish fry of the same species and same age, the specifications should be uniform, with little difference in body length and body weight, thick back muscles, bright color, intact scales and fin rays, normal activity, and strong upstream-swimming ability. After being taken out of the water and placed in a basin, the gill covers should not open, the tail should not bend, and the fish should keep jumping, with no wounds or parasites on the body surface.

Fish fry disinfection Some farmers do not disinfect fish fry at all when releasing them, resulting in a high disease rate, and drug treatment is not ideal. In fact, as long as fish fry disinfection is done well, disease prevention can often achieve twice the result with half the effort. When disinfecting fish fry, pay attention to the following 3 points: First, the medicine should be prepared and used immediately, and clean water should be used to prepare it. Do not use fertilized water, and avoid direct sunlight when soaking the fish fry in the medicinal solution. Second, the drug dosage must be accurate, avoiding insufficient dosage or excessive medication. Third, the soaking time should be appropriate. If the fish fry are found to be unable to endure it, water should be added immediately or the fish fry should be placed in another container.

Release method and time Before the fish fry are put into the pond, first strictly check whether the effect of the pond-clearing drug has passed. Method: place a small cage net in the fish pond to be stocked, put dozens of fish in it for trial, and observe overnight to see whether their activity and floating-head condition are abnormal. If symptoms such as restlessness, floating-head struggling, and darting around appear, it means there is still residue of the pond-clearing drug, and they must not be released immediately. Only after the drug has completely disappeared can the fish be released. In addition, before the fish fry are put into the pond, a fine-mesh net must be used to pull through the whole pond 1~2 times to remove harmful insects, frog eggs, wild trash fish, and other organisms in the pond that may harm the fish fry, ensuring the safety of the fish fry after they are put into the pond. It is best to release the fish fry at noon on consecutive sunny days, when the fish fry adapt fastest and the survival rate is also highest. On windy days, the fish fry should be released at the windward area of the fish pond, so as to avoid being blown to the pond edge and dying when released at the leeward area.

Pay attention to the temperature difference when putting into the pond When the fish fry are put into the pond, note that the temperature difference between the water holding the fish fry and the pond water must not exceed 3°C. If the temperature difference is too large, adjust the water temperature in the container to make it close to the pond water temperature. For fish fry transported in oxygen-filled plastic bags, they need "seedling hardening" treatment when put into the pond. When the fish fry are put into the pond, they should also be counted accurately.