Fish Once the water quality of the pond deteriorates, the fish will suffer from hypoxia, poisoning, and even death. Therefore, it is very important to do a good job of water quality modulation management.

1. Timely dredging. The silt thickness of intensive fish ponds generally increases at a rate of about 10 cm per year. Retaining silt of suitable thickness (15-20 cm) in the pond can play the role of maintaining fertilizer, supplying fertilizer and buffering water quality, but too thick silt will cause harm to aquaculture and must be dredged and improved. When dredging the pond, first drain the pond water, carry out manual or mechanical (mud pump) dredging or carry out water dredging with the help of submersible underwater dredging machine, or plant some emergent or submerged plants in the pond to improve Substrate.

2. Apply bleach. In order to kill germs, parasites, etc. in the pond, some aquaculture    farms or farmers use a large amount of quicklime and bleaching powder. Don't you know that while killing germs and parasites, it also kills a lot of algae in the water, resulting in a thin pool of water. The residual bait of the feed and the ammonia nitrogen, nitrite nitrogen, carbon dioxide and other gases produced by the decomposition of fish manure lose the phytoplankton that use them as a nutrient source, and these harmful gases accumulate in large quantities in the water body, causing fish poisoning. Therefore, bleaching powder should be properly applied to disinfected ponds.

3. Feed with temperature. Feeding feed to adult fish should adopt interval feeding method in spring. Usually 2 to 3 days to feed 1 time. From Grain Rain to summer, the amount of fish food gradually increases, and the feed is changed from interval feeding to daily feeding. It is best to feed it on a fixed food table to avoid waste of feed and pollution of water quality. The most suitable water transparency for fish culture in ponds is generally 25-30 cm. If the transparency is too small, the amount of fertilization should be reduced or stopped immediately; if the transparency is too large, more fertilizer should be applied to improve the water quality, generally once every 5 to 7 days. Fertilizer, 50-80 kg of decomposed organic fertilizer or 2-4 kg of chemical fertilizer per 0.067 hectare each time.

4. Regularly measure the water. Fish are suitable for growing in neutral or slightly alkaline water, the fish pond has a large amount of organic matter, and the water quality is often acidic. Therefore, it is necessary to regularly take water samples from fish ponds to measure pH, dissolved oxygen and ammonia nitrogen, at least once every two weeks. If there are 72 grams of ammonium ions per cubic meter of water, 1/3 of the fish pond water must be replaced. It is best to replace the pond water with rich phytoplankton to improve the water quality and increase the dissolved oxygen in the water. If necessary, use an aerator for 1 to 2 hours a day. For fish farming all the year round, every 0.067 hectares of ponds with an average water depth of 1 meter are sprinkled with 20-25 kg of quicklime dissolved water, once every half month, so that the fish are in the best growing water environment. It must be noted that the pH value is higher than 8.5, which is not conducive to the growth of fish. When the pH value exceeds 10 or is lower than 4.5, it will cause the death of pond fish.

  5. Beware of accidents. Once dead fish are found due to deterioration of water quality, more than 1/3 of clean water should be injected immediately to reduce the concentration of ammonia nitrogen and nitrite nitrogen in the water. Every cubic meter of water should be splashed with 25 grams of salt, which can reduce the nitrous acid in the water. Repeat the operation until the ammonia nitrogen is adjusted to the normal range.