How to prevent fry hatching abnormal embryos

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 hatching tank is rough, it must be grinded with a grinding wheel to obtain a suitable density when laying eggs sparingly. Generally, about 800,000 eggs are laid per cubic meter of water. The hatching water should be clean without pollution and have a large flow; Sprinkle the lime slurry in the reservoir to adjust the pH to maintain the pH between 7 and 8; if it is found that a small amount of eggs have hatched in the hatchery, remove the water inlet valve and splash the potassium permanganate solution. Into the hatching pool, so that the pool of water was 5 ~ 10ppm concentration, and maintained for 5 to 8 minutes, after treatment, the egg membrane of the fish will become more solid, not easy to damage, to prevent the role of early release. Over-ripe fish eggs, as well as fish eggs produced by malnourished broodstock, are most likely to cause abnormal embryonic temperature changes, especially in the fertilized stage of eggs, before and after cleavage, and before and after the release of the eggs, drastic changes in water temperature will cause abnormal embryos to increase. . 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 fry incubating stage. When it invades a large number of hatching pools, it will bite fish eggs or bite dead fish. Therefore, spawning ponds and hatchery pool water 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. Mi Qian water 200 milliliters of medicine, in the water temperature of 30 Â°C ~ 28 Â°C, 10 to 30 minutes to kill the sword in the pool of water. 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.
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Posted on January 20, 2021