Winter management of fish
With the decrease of water temperature, the reproduction speed of microorganisms weakens, and fish diseases before and after overwintering also become significantly less. However, some trichoderma species that are adapted to low temperatures, such as fungi and parasites, are still lurking in water bodies, and can cause fish body watery mildew and disease at any time. The parasite-caused gill disease, especially after the nets are pulled over, is even more pronounced. However, due to the weakening activity of fish in winter and the influence of water temperature and environmental factors, it is difficult to find the diseased fish on the water surface. If a fish disease is found after freezing in the pond, further treatment will be troublesome and will not be effective. Therefore, the prevention of fish pond medication should be done well before wintering. The method is: in the warm afternoon, 200 grams of bromochlorohydrin should be splashed once per mu. Every 2 to 3 days after the mu, 200 ml of wheel extinction (matrine) should be splashed once, which can effectively prevent winter diseases. Second, increase fish fat, improve fish physique Many fishermen and farmers all know that fish have different degrees of weight loss after wintering, and generally the weight of four domestic fish can be reduced by about 5%. In particular, the weight loss of grass carp and carp is even greater. This is because the fish enter semi-hibernation after they have stopped eating. Although fish do not need a lot of energy because of low temperature, fish will still have some activity at lower water temperatures, which will require some energy in the internal organs of the fish to sustain life. Some fishermen think that it is not scientific to feed some low-quality bait after the fish grows into adult fish to reduce the input of fish ponds. In fact, it is not scientific to feed fish in the first 20 days or even within a month before the fish stops eating. High-quality concentrated feeds, such as squid, should have more than 32% protein, and grass carp should have more than 28% protein. It is best to add about 5% corn to the feed to increase the feed's effective sugar content, thereby increasing the fish's fat and increasing the muscle thickness of the fish. In this way, the fish body can avoid the frostbite caused by the cold weather, and effectively reduce the problem of “dropout†caused by overwintering. Third, strengthen pool management and improve water quality After the winter fish ponds are frozen, the water temperature in the bottom of the pool is not necessarily very low. The residual bait, feces, and some dead plankton plants and sediments deposited on the bottom of the pond will still be fermented and decomposed. This will not only consume dissolved oxygen in the water, but also produce similar water. Ammonium nitrogen, hydrogen sulfide and other harmful substances are common in summer ponds. Coupled with the influence of factors such as low temperature in winter, shortening of illumination time, reduction of microorganisms, and decrease of dissolved oxygen, harmful substances are difficult to be decomposed and transformed at low temperatures. Therefore, eliminating harmful substances in water at low temperatures is much more difficult than in summer. . Therefore, for wintering ponds, it is advisable to sprinkle one to one kilogram of biological agent EM bacteria at a water temperature of not less than 18°C, or to use “magnetic water quality improver†(aluminum sulfate and strong body compounds) for 1 kilogram. Spill once. When the fish is completely stopped, a 150-200 ml “rotifer chew†(main component acetate) is used to effectively prevent the occurrence of zooplankton in the water body, thus ensuring the water quality of overwintering ponds. Fourth, postponed the stoppage time, reasonable feeding in winter Common water-fat fishes have obvious performance in stopping the water when the water temperature is below 10°C. Most of the fish farmers are also accustomed to no longer feed the fish. After many tests conducted on weeds, grasses, cockroaches, and clams at water temperatures below 10°C, these fishes give a very small amount of bait every day and they can quickly devour them in a short period of time. It can be seen that the later the fish's winter stop time is, the better. Even after the food is stopped, it is beneficial to choose to feed a small amount of feed on a sunny afternoon. Fifth, do a good job of increasing oxygen in the water body to ensure safe wintering The freezing winter is ice-cold water. In order to allow the fish to safely pass through the winter, we recommend that the aerator should be deflected near the material table before freezing, and the machine should be turned on for about half an hour each day to ensure that the aerator is in close proximity to the cold. The winter does not freeze, in order to achieve the long-term ventilation of the water under the ice, increase the role of dissolved oxygen in the water. In addition, for the seepage pond, it is necessary to regularly add new water to ensure that the depth of the ice water is preferably between 1 and 1.5 meters. When adding water, be sure to add water from the bottom up, do not form a second ice, to prevent the fish from freezing and freezing to death. At the same time, it is necessary to reasonably clean the snow in heavy snow weather to ensure the photosynthesis of phytoplankton beneath the ice. In short, the safe wintering of fish ponds is a key step for the bumper harvest in the coming year. It is hoped that the majority of fishermen will change their minds and use scientific methods to do a good job of fish wintering. Sinoscope Electric Drill,Nose Ent Instrument,Ent Sinus Electric Drill,Ear Electric Drill ZHEJIANG SHENDASIAO MEDICAL INSTRUMENT CO.,LTD. , https://www.shendasiaomed.com