How Do Fish Live Under Ice? | Discover How

This article will focus on the question: how do fish live under the ice? Fish are able to survive through the freezing temperatures of winter partially because they are cold-blooded creatures. 

But aside from this factor, we’re diving deeper into the biological reasons they handle the cold. You’ll also learn about the types of fish that survive well beneath the ice. And we’ll explore the different living conditions and factors that make it possible. Keep reading to get the rundown.

Types of Fish Anglers Will Find Beneath Ice

Depending on the body of water you’re fishing (lakes, harbors, bays, etc.), the types of fish beneath ice will vary. Most commonly, though, ice anglers bait up for the following beneath the surface:

  • Whitefish 
  • Crappies
  • Perch (yellow perch)
  • Walleye
  • Trout (lake and rainbow)
  • Sunfish 
  • Small- and large-mouth bass
  • Pike 
  • Bluegill 

Most of these fish are found in lakes and rivers, though you may find bass in a stocked pond.

How Fish Survive Under the Ice

When we consider what makes it possible for fish to survive freezing water, we need to look at several factors:

  • What goes on biologically in fish during winter weather?
  • How do fish find food and what do they eat during winter weather?
  • How much do fish sleep under ice?
  • What conditions are necessary in the body of water for fish to survive beneath ice?

Biological Factors

One common question regarding fish in frozen lakes/ponds is how they handle the frigid temperatures. While the air temperatures above the surface may be at or below freezing for the anglers, it’s different underwater. 

In a typical frozen lake, the below-surface water temperature will maintain at least a few degrees above freezing. It’s still very cold, but not as detrimental to fish as it would be to us, warm-blooded humans.

We know that fish are cold-blooded, which is part of what makes living beneath the ice possible for them. As the water temperatures lower in the winter, fish’s body temperatures will do the same to adapt. 

Aside from temperature, though, fish will also undergo metabolic changes. Fish must slow down to conserve energy, without stopping altogether, as they need movement to breathe. And as their bodily functions slow down, they require less oxygen to maintain their health. This means that they also adapt to lower water oxygen levels as a result of less sunlight getting through the ice.

Furthermore, certain fish even go into “torpor”, such as pond fish like koi or goldfish (but you probably won’t encounter them as an ice angler). This is a biological state that’s similar to, but not the same as, hibernation. In torpor, fish require much less oxygen to survive.

Eating Habits

Anglers often wonder about how fish find food beneath the ice, too. Well, it’s not as hard as one might think since these creatures are so adept at adapting.

Certain fish will seek out food more often than others if they’re capable of raising their internal temperatures. But the other fish that really slow down in winter will have prepared for this season by packing on fat. The slower fish will spend most of their time hiding/burrowing in secluded areas so they don’t become prey themselves.

But, luckily for the feeders, even beneath frozen surfaces, bodies of water still contain the larvae of certain insects. Common prey for small fish like crappies and bluegill include midge larvae and little blood worms. These make great winter food for the fish who do move around a lot and scavenge.

Keep these feeding habits in mind when you go ice fishing. This way, you can more easily pinpoint the types of bait to use on perch and other fish in winter.

Sleeping Habits

As for sleeping habits, we previously mentioned the state of torpor that some fish enter beneath the ice. While fish won’t exactly sleep through the entire winter (or hibernate as some species do), they do slow down. Everything in their usual routine becomes less active, and they require less to sustain themselves. 

Otherwise, though, fish will still maintain a regular “sleep” schedule in the wintertime, beneath the ice. Note that sleeping for fish isn’t quite the same as it is for other creatures, but they do float and rest.

Withstanding the Conditions

Now, you might still be wondering how fish can survive beneath a body of water when it’s completely frozen over. This is a good question since fish do require a decent amount of oxygen to breathe through their gills.

Fish being able to survive beneath the frozen surface of a body of water requires some form of ventilation. Without some holes/vented areas in the ice, gasses from decaying underwater matter can build up and poison the fish. 

Luckily, though, in larger bodies of water, it’s less likely for there to be a lack of ventilation. Whether it’s due to anglers, human interference, or the elements, frozen lakes are usually ventilated enough for fish to survive. 

Final Thoughts – How Do Fish Live Under Ice?

The reason it’s possible to fish in the winter is that fish sustain their health and adapt to cold temperatures. As cold-blooded creatures, fish like crappies, perch, and trout, slow down metabolically and require less oxygen. 

Their internal temperatures will lower to be closer to that of their surrounding environment. And they either stock up on food before slowing down, or they scavenge for insect larvae in the mud. While they don’t hibernate completely, fish survive just fine beneath a frozen body of water, as long as there is ventilation.

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