Four ways to get rid of wild fish

When adding water, changing water and feeding water plants in intensive ponds, it is inevitable to mix with wild miscellaneous fish or eggs such as rice strips, wheat ear fish, crucian carp, @ # @ 237 fish, grass shrimp and so on. These wild miscellaneous fish not only have strong feeding capacity, large food intake, low economic value, but also have fast reproduction speed, and in addition, carnivorous ferocious fish such as snakehead and catfish can also swallow farmed seedlings. Therefore, various measures must be taken to eliminate wild miscellaneous fish in culture management.

1. Prior to killing the wild miscellaneous fish in the pond, the pond water should be drained and the bottom of the pond should be frozen and insolated for a period of time before the fry is released, then the pond water of 20cm to 30cm should be added and sterilized with quicklime and tea seed cake respectively. Dosage: quicklime 1500-2250 kg / ha, tea seed cake 750 kg / ha. Usage: sprinkle the whole pond after raw lime slurry, turn the sediment with iron palladium the next day; soak the tea seed cake for one day and night, sprinkle the whole pool with dregs and juice, check the death of wild mixed fish 3 hours later, and fish out the dead fish. If there are still wild miscellaneous fish that are still alive, they need to be killed again.

two。 There are three main ways to put an end to wild miscellaneous fish entering the crab pond through wild miscellaneous fish: first, when adding and changing water; second, when transplanting aquatic plants such as aquatic plants and water peanuts attached to crabs on the surface of the water surface, bring wild miscellaneous fish eggs into the crab; third, when feeding aquatic plants. A tight-eye mesh bag made of polyethylene or yarn silk with a mesh of 2mm is installed at the inlet to effectively prevent wild miscellaneous fish, eggs and aquatic insects from entering the pond; the transplanted or fed aquatic plants such as water peanuts can be exposed to the sun for 1 day or 2 hours, or soaked in medicine (5 mg / L copper sulfate solution, 30 mg / liter tea seed cake extract, etc.) for 2 hours.

3. Zhang catches wild miscellaneous fish and sets up fish nest. the first is to use a dense-eyed net to make a 3-square-meter fish, which is set near the water inlet, and the bait that wild miscellaneous fish like to eat is placed on it, which is picked up once every half an hour or so to remove wild miscellaneous fish. Second, the ground cage is set in the crab pond and caught once or twice a day. It is worth noting that the top of the cage should be opened high out of the water, so that the crabs that enter the cage can climb out of the water. The third is to copy the net to catch wild miscellaneous fish at the bottom of the water peanut community, and the fourth is to hook or fork to catch the adult fish in the pond, and the eggs or juvenile fish are found in the breeding season. Fifth, in the wild miscellaneous fish breeding season, set up the fish nest in the fish pond with tree roots, brown slices and aquatic plants, let the wild miscellaneous fish lay eggs on the fish nest, and remove the fish nest in time.

4. The practice of feeding carnivorous fish to eat wild miscellaneous fish has proved that biological removal of wild miscellaneous fish is also effective. Adult fish ponds or two-year-old fish ponds can co-culture carnivorous fish such as mandarin fish, @ # @ 243 fish, big-mouth catfish, but the number of mixed culture should not be too much, and the size should be less than 2x3 of domestic fish. It must be recorded when it is put in, and it must be caught in dry ponds at the end of the year, so that all carnivorous fish can be caught so as not to cause harm to domestic fish. The carnivorous fish species such as mandarin fish, Pelteobagrus fulvidraco, warped-billed red ship and other carnivorous fish that do not pose a threat to crabs are placed in the crab ponds. According to the number of wild miscellaneous fish in the crab ponds, generally from April to June, every hectare of water is covered with 150 mandarin fish of more than 5 cm, or 4500 Pelteobagrus fulvidraco with a body length of 3 cm, or 300 species of warped-billed red fish with a body length of 10 cm. Moreover, a certain amount of valuable aquatic products can be harvested, which can increase the efficiency of breeding by 10% to 20%.