How Do Small Fish Survive the Winter? A Detailed Guide to Fish Overwintering Methods

When it comes to winter, it undoubtedly gives people a feeling of cold, especially in northern regions, where every winter brings heavy snow, rivers stop flowing because they freeze over, and in earlier times people even had to stockpile vegetables to get through it. Since winter is so cold and freezing, then as creatures at the bottom of the food chain, how do small fish get through the winter?

1. How Do Small Fish Overwinter

Most fish do not hibernate. When the weather turns cold, fish live in the middle and lower layers of the water. Water between 0 and 4 degrees exhibits a phenomenon of contracting when heated and expanding when cooled, so the warmer water actually sinks downward; that is to say, the water temperature at the bottom is 4 degrees, which is why the water never freezes all the way to the bottom. The water temperature in the lower layer of the river is relatively higher, and it also causes the small fish to reduce their activity. Only when the weather is clear do the small fish float up to the surface to move about.

But some fish do hibernate. Carp often overwinter at the bottom of the river, gathering in groups of dozens to as many as a hundred at depressions in the riverbed, forming a circle with their heads pressed tightly together, breathing slowly, with their gill covers moving very slowly, and their body temperature can drop to 1 degree Celsius, not “reviving” and dispersing until spring. When hibernating, the tench sleeps even more deeply than the carp; if you dig out a tench hibernating buried in the river mud, you cannot tell it is alive without hitting it with a stick.

2. How Do Farmed Fish Overwinter

1. Feed the fish at ten in the morning. By 10 o'clock the air temperature has gradually risen, and the difference between water temperature and air temperature is relatively small; starting to feed the fish at this time reduces, to a certain extent, the impact of low air temperature on the fish.

2. Pay attention to adjusting the water temperature so that it stays within the range suitable for the fish's growth. In winter, the water temperature can be adjusted to around 20°C to narrow the difference between water temperature and air temperature.

3. Tropical fish need a heating rod or ultraviolet lamp to maintain the temperature. If they are just ordinary fish, such as goldfish, no care is needed in winter, and no heating measures are required.

The above is some little knowledge about fish overwintering. Friends, do you know how fish overwinter now?