What Kills Fish Under the Ice? 😳

Added: 2026-05-19

[00:00:00]Do you know why people pump air under frozen lakes? You might think it is some kind of ice fishing trick, but in reality, it is the exact opposite. When a lake becomes sealed under a thick layer of ice during winter, the water can barely receive new oxygen from the air anymore. But oxygen under the ice is still constantly being used up. It is consumed by decaying plants, microorganisms, and the fish themselves.

[00:00:22]Oxygen levels slowly begin to drop while harmful gases build up beneath the ice.

[00:00:26]The fish do not freeze to death. They slowly suffocate and become poisoned.

[00:00:30]You might wonder why people do not simply cut a hole in the ice because a normal hole has very little effect and quickly freezes over again. Pumping air under the ice works very differently.

[00:00:40]The flowing air constantly disturbs the water, helping oxygen dissolve into the lake. And because colder oxygen rich water is denser, it naturally sinks deeper into the lake. At the same time, the air flow pushes harmful gases outward. So, this is basically a breathing machine for the entire lake, giving fish a real chance to survive the winter.