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1. Water quality management. There is little rain in winter, which easily causes the water level of the fish pond to drop. Some fish farmers like to make the fish pond water shallow so that the fish can be exposed to the sun for heating purposes. In fact, shallow ponds, rapid water temperature changes and large temperature differences in winter will bring disadvantages to fish growth.
The main ways to manage water quality are:
One is to raise the water level of the pool. Properly increasing the water level in winter can increase the water body capacity and maintain a relatively stable water temperature. Usually, the fish pond water level should be kept at about 2 meters. When the water level drops by 10 to 15 cm, new water must be added in time to stabilize the water level.
The second is to regularly adjust the water quality. New water should be added every 20-30 days, 20-30 cm each time, and the old water should be properly discharged.
The third is to increase calcium and phosphorus. Sprinkle quicklime solution once a month to increase the calcium concentration of the water body; add phosphate fertilizer once a month to increase the phosphorus concentration of the water body and enhance the cold resistance of the fish.
The fourth is to take aeration measures. As the temperature drops, the temperature of the surface water decreases, and the density increases and sinks. The bottom layer is hypoxic and anaerobic, which will cause severe hypoxia in the upper water body. In addition, in winter, the light time is short, the photosynthesis of phytoplankton in the water is weakened, and the oxygen production is reduced, which will also cause insufficient dissolved oxygen in the aquaculture water.
Therefore, it is necessary to take timely aeration measures in winter, and insist on opening aeration facilities from 12 noon to 2 pm every sunny day to promote the convection of surface water and bottom water, make the dissolved oxygen in the pond water even and reasonable, and increase fish appetite and disease resistance. , Prevent the occurrence of the phenomenon of dead fish in the hypoxic pan-pond
2. Reasonable feeding. Reasonable feeding can improve fish disease resistance. In sunny and warm weather, fish can still eat, so it is necessary to supplement and feed the concentrate appropriately to supplement the energy of fish life activities and increase the survival rate. Generally, it is fed once every 3 to 5 days, and the daily dosage is 0.5% to 1.0% of the fish body weight. When the water temperature rises above 8°C on a sunny day, the fish activity will increase, and the amount of bait should be increased appropriately. The specific feeding should be flexibly controlled according to the eating situation of the fish.
3. Disease control. In the cold winter season, because the water temperature is low, the immunity of fish is reduced, disease resistance is weak, and they are susceptible to infection and invasion by fungi and parasites. Strict disease prevention measures must be taken and water body disinfection performed regularly. For saprolegnia caused by bumps or frostbite of the fish, you can sprinkle it over the whole pond with 2～3ppm methylene blue or 2～3 times. In addition, for trichoderma and oblique tube worm disease, you can use a mixture of copper sulfate and ferrous sulfate (prepared at 5:2) to splash in the whole pond.
4. Insist on patrolling the pond. Visit the pond once a day, morning, noon, and evening, pay attention to observe the pond water color and fish activity, and make records. When the temperature drops to 3～5℃, increase the water level of the pond to a better depth, and check whether the inlet and drainage channels are unblocked. If the pool surface freezes, shorten the freezing period as much as possible. After the temperature rises before the beginning of spring, the water in the pond should be drained to increase the temperature of the fish pond as soon as possible, so as to encourage the fish in the pond to eat early and increase the growth period.