In the hatching process of fish fry, the phenomena of early release and malformation of embryo occur occasionally, which seriously affects the emergence rate. What preventive measures should be taken? Where the wall of the hatchery is rough, it must be smoothed with a grinding wheel. Gradually grasp the appropriate density when laying eggs, usually about 800,000 eggs per cubic meter of water; hatching water should be clean and pollution-free, and have a larger flow; acidic water, can be poured in the reservoir of lime slurry adjustment, so that The pH is maintained between 7 and 8; if a small amount of fish eggs in the hatching pond are found to be released in advance, the small inlet valve may be closed and the potassium permanganate solution may be poured into the hatching tank to make the pool water 5 mg/well. Raise the concentration of ~10 mg/L and keep it for 5 minutes to 8 minutes. After treatment, the egg membranes of the fish eggs will become firmer and harder to break, which will prevent premature release. Over-ripened fish eggs, as well as fish eggs produced by malnourished broodstock, are most likely to form deformed embryos. Changes in temperature, especially at the fertilization stage of the eggs, at the beginning of cleavage, and before and after the release of the membrane, can lead to an increase in abnormal embryos. Poor hatchery water quality also affects the normal development of the embryo and produces deformed embryos. Therefore, once a year's fry breeding work, it is necessary to do a good job of broodstock cultivation, but also to select the right time for the appropriate broodstock production. Sword mink is the biggest enemy of the fry hatchery stage. When it invades a large number of hatching ponds, it will bite fish eggs or bite dead fish. Therefore, spawning ponds and hatching pond waters must be strictly filtered. If it is found that there is more water in the hatchery pool, close the water inlet valve properly. The water intake is based on the fact that the fish eggs can be tumbling without sinking, and then 80% of the dichlorvos emulsion is poured into the hatching tank and immediately stir manually, every cubic meter. Rice pond water 200 milliliters of medicine, when the water temperature of 28 °C ~ 30 °C, 10 minutes to 30 minutes can kill the pool of water swords. Or drill a few holes in a plastic bottle filled with 90% crystal trichlorfon, and hang it in the reservoir to the water supply port of the hatchery to poison the sword water cricket. Face Shield,Covid Face Shield,Best Face Shield,Face Shield Covid Zhejiang Lanhine Medical Products Ltd. , https://www.lanheyiliao.com