How do fish spend the winter?

Basic conditions of overwintering pool

1. Water depth: The unfrozen water layer of the wintering pond should be above1-1.5m. Because the wintering pond keeps leaking during long-term freezing, it is not enough to consider only the water depth when entering the pond. It is necessary to pay attention to the change of water level in the wintering pool and take timely water replenishment measures to keep the water level in the wintering pool within the required range.

2. Bottom material: The bottom of the pond should be flat, and the thickness of silt should be about 10 cm. Because sludge contains a lot of humus, it can supply fertilizer, keep fertilizer and adjust water quality, but excessive sludge will consume a lot of oxygen in the process of decomposition, which will easily lead to hypoxia. Therefore, the silt in the wintering pond should be removed as much as possible.

3. Water quality: It is not appropriate to use all the old water in the original pond for fish wintering. It is best to mix more than half of fresh water, and the transparency of water should be greater than 35cm. There is a certain amount of phytoplankton in the water. Using photosynthesis under ice to supplement oxygen in water can improve water quality.

Extended data:

There are two main reasons for the death of cultured fish in low temperature season:

1, hypoxia. Because the aquaculture waters are covered with ice and the water is isolated from the atmosphere, the oxygen in the water cannot be replenished from the atmosphere; The snow on the ice layer reduces the light intensity in the water area, and the photosynthesis of aquatic plants weakens or even stops, which basically cuts off the source of oxygen. However, the decomposition of organic matter in water and the respiration of animals and plants continue to consume oxygen. When the dissolved oxygen is too low, a large number of fish will suffocate and die.

2. Low temperature. The water temperature under ice is usually below 4℃. At this time, some cultured fish basically stopped eating, and their life activities were all maintained by the nutrients stored in their bodies. For example, if the fish is thin, it is not only difficult to survive during the long ice age, but also easy to get sick. Long-term low temperature below 0.5℃ will also freeze some fish to death.

Baidu Encyclopedia-Cultured Fish Overwintering