Causes of overwintering death of fish species and its management measures

The temperature dropped seriously after the Beginning of Winter, which is also a test for fish farmers. Fish species need to be managed through the winter in order to improve the overwintering survival rate of fish species. The following collates the causes of overwintering death of fish species and management measures, hoping to help friends in need, let's take a look.

I. causes of death of fish species overwintering

1. Water anoxia

The pond did not clean up the silt for many years, and the silt deposited too much, resulting in the deterioration of pond water quality, the increase of oxygen consumption, and the anoxic water level of fish species. Pond water is too thin 'rich in few plants, weak photosynthesis, so the oxygen produced can not meet the consumption of water organisms, coupled with fertilizer and water measures can not keep up, resulting in anoxic water level of fish species. If there is leakage in the pond, but there is no timely replenishment of new water, resulting in the pond water level is too shallow, resulting in anoxic fish water level. After freezing in winter, the ice is too thick or too much snow, the sun can not shine into the pool water, can not carry out photosynthesis, resulting in anoxic water level of fish species.

2. Harmful substances exceed the standard

After the organic matter deposited in the pond is decomposed, harmful substances such as ammonia nitrogen, nitrite, hydrogen sulfide and other harmful substances will seriously exceed the standard, resulting in fish poisoning and death.

3. The size of fish species is small.

The physique of fish species also affects the survival rate of overwintering, poor physique of fish species, less body fat, far from being able to meet the needs of nutrition during the overwintering period, but also cause the death of fish species.

4. Improper operation

The physique of fish species is poor in winter, and if the incidence of fish increases due to injury infection in the process of pulling nets and merging ponds, it will eventually lead to the death of fish species.

II. Isolation measures

1. Select the pond

As fish species overwintering ponds, be sure to choose close to the water source, leeward to the sun, quiet environment, good water retention, less silt, flat pond.

2. Prepare before stocking

For ponds with more silt, especially Laotangkou, the excess silt at the bottom must be removed before stocking, leaving only about 10 centimeters of silt. After treatment, it is also necessary to clean the pond with quicklime, dissolve the lime with water and sprinkle it all over the pool while it is hot.

3. Stocking

In the stocking, we must pay attention to the specifications should be large rather than small, in general, the requirements of overwintering fish stocking specifications should reach more than 10 cm. The stocking density depends on the pond conditions, the size of the fish species and the water quality of the source. Stocking time should not be too early, early water temperature is too high, fish species are more active, extremely vulnerable, in addition, in the stocking need to soak in salt water for about 5 minutes, in order to kill pathogens and parasites.

4. Feed feeding

During the overwintering period, the fish can still eat when the weather is clear, so some bean cakes should be fed appropriately when overwintering, and throw into the deep water as far as possible to meet the feeding needs of the overwintering fish.

5. Water quality control

Generally, water should be added once a week and changed once a month. The depth of adding water is 10-20cm, and 20% of the water should be changed. At the same time, quicklime should be used regularly to regulate the water quality, keeping the pH value between 7.0and 8.5cm. Turn on the oxygenated social security at the right time to ensure adequate oxygen supply.

The above is the introduction of the causes of overwintering death and management measures of fish species. I hope it can help you. If you want to know more about it, please follow us.