Overwintering management of freshwater fish

2023-11-27

Qingdao Zhongren Animal Medicine Co., Ltd

Zhongren Aquatic Products

The overwintering period of freshwater fish culture in northern China is longer, mainly from November of that year to March of the following year, and the overwintering temperature is low. After the three breeding seasons of spring, summer and autumn, a large number of residual bait, feces and other organic matter are deposited on the bottom of the pond, which is easy to breed a large number of harmful bacteria and produce a large number of harmful substances. After entering the winter cooling period, due to the large difference in water temperature between the upper and lower layers, the upper and lower layers of the pond are prone to strong convection, causing a large number of harmful bacteria and harmful substances to enter the water body. If these organic matter and harmful substances cannot be disposed of in time, the water temperature will rise in spring next year, which will easily cause water quality deterioration and threaten fish culture.

Key points of fish management during wintering are as follows

1. water level management

As the water temperature drops, the bottom temperature is significantly higher than the surface, and the overwintering fish will be concentrated in the middle and lower layers of the pond, so raising the water level will reduce the probability of frostbite in winter fish and reduce the incidence of water mold in spring. Therefore, before the advent of winter, the water level of the pool (more than 2 meters) should be raised in advance.

2. aerator use

As mentioned earlier, as the temperature drops, there will be water convection. Convection will bring harmful substances at the bottom of the pool to the water body, which will have a serious impact on the fish before overwintering, so pay attention to the opening of the aerator. It is best to turn on the aerator in the afternoon to fully mix the upper and lower water bodies. In addition, turning on the aerator in the afternoon also helps to increase the temperature of the water body and prolong the growth time of the fish. In addition, increasing the opening time of the aerator can oxidize the organic matter in the water body and reduce the growth of oxygen consuming harmful bacteria in the water body.

3. fish feeding management

Before sealing the ice, feed should be fed as much as possible. The main purposes of feeding are as follows:

1. Accumulate nutrition, smooth overwintering

Fish overwintering will consume a lot of energy, especially in the north, it is impossible to feed and manage after ice sealing in winter, so it is necessary to feed as much as possible before ice sealing, so that fish can store sufficient overwintering energy, so that fish can survive the cold winter, and sufficient energy will also reduce the probability of fish disease in spring.

2. Prevent the overwintering period is too long, resulting in the degradation of hepatopancreas and intestinal function

Long time overwintering will cause the liver and pancreas of fish volume and cell function degradation; long time jejunum will also cause fish intestinal atrophy or abnormal peristalsis, will increase the probability of early spring disease. Especially after the spring opening more likely to break out digestive system problems. Therefore, it is suggested to feed as much as possible before sealing the ice, once a day, or once every 1-2 days according to the weather and fish feeding conditions. In the process of feeding, you can add products to improve the body's immunity: aquatic special multi-dimensional, astragalus polysaccharide and hepatobiliary Kangtai.

IV. Water quality and bottom quality management

The focus of water quality control is to ensure that harmful substances (ammonia nitrogen, nitrite, hydrogen sulfide, etc.), harmful bacteria do not exceed the standard, in addition to the need for stable algae phase, to ensure that the water quality in the best state into the wintering period.

Before sealing the ice, conduct fertilizer and water operation in advance to cultivate the algae phase of the water body to ensure the stability of the algae phase under the ice after sealing the ice, and the dissolved oxygen in the water body is sufficient to prevent hypoxia after sealing the ice.

Before sealing ice, the bottom material can be completely improved, and the bottom material can be changed to overlord (100 mu/barrel) to reduce the organic matter content in the bottom material and kill excessive harmful pathogens at the bottom of the pool.

5 Disease prevention and management

During the wintering period, fish are most likely to be infected with mildew and tail rot. If it cannot be effectively controlled before overwintering, large-scale deaths will erupt once the water temperature rises in the spring. Therefore, it is necessary to do a good job in the prevention of insecticidal and disinfection before overwintering. The wheel finger ring can be used to clean and add salt (1.5 mu/bag) to kill insects, and the next day it can be disinfected with Zhongren gold iodine (8 mu/bottle) to prevent bacterial and fungal infections from causing diseases such as gill rot and body rot.