Last Updated on September 17, 2019 by Aiden Lindow

How To Keep Your Pond Warm In The Winter

In this guide, you’ll learn exactly how to keep your pond warm in the winter. Your pond can get cold and ice over quite fast and that’s why you need to be prepared.How To Keep Your Pond Warm In The Winter

When a pond’s temperature decreases or when a pond ices over, you will see your fish moving slower and always near the bottom of the pond.

By following these steps will ensure you keep your pond warm in the winter so your fish won’t die and help have a healthy environment.


How To Keep Your Pond Warm In The Winter


Turn Off Your Water Features

Turning off your pump and any other water features might seem counter-intuitive when it comes to preventing ice, but it can prevent ice from forming way better than the flow of water.

When the water comes into contact with the cold air, the water will be cooled.

By turning off the pump and other water features it will prevent the water from cooling anymore than it already is.

During the summer, many people increase the number of water features they have to keep their pond cooler.

By turning off any water feature it will, in turn, keep your pond warmer during the winter.


Use Heaters

During the cold months of winter using a heater never hurts.

If you have a small pond using two or three small heaters can really help your pond.

The heaters I use for a small pond are fish tank heaters.

By using two or three of these small heaters it can increase the temperature of your pond by about 10 degrees depending on the size of the pond.

I also recommend setting the heaters to the highest setting.

You do not have to worry about your pond getting too hot like a fish tank, as the pond is much larger than a tank and most ponds are located outside.


Make Sure Your Pond Is Deep Enough

How To Keep Your Pond Warm In The Winter

Making your pond deep is a common trait to anything beneficial when it comes to building ponds.

In the summer it keeps the pond cool and in the winter it will keep the pond warm.

If your pond is too shallow it can easily freeze and lead to many problems.

Giving the fish a deep spot in the pond allows them to swim away from the surface of the pond.

As the fish gets further down from the surface, the warmer it becomes. The surface is colder as that is what comes in contact with the outside elements.


Hibernation Of Fish 

During the winter months, fish will start to hibernate.

The metabolism of fish will decrease exponentially as they do not need to use very much energy because they are already the temperature of the water.

In order for the fish to swim around in the cold water, it takes way more energy during the winter than during the summer.

If you see your fish laying on the bottom and having very little motion you do not have to worry.

Just like any other animal that is cold they will hunker down, stay still and wait it out.

If the fish started to swim around they would lose valuable energy they could be using to stay warm.


Feeding Fish

How To Keep Your Pond Warm In The Winter

During the cold winter months, try not to feed your fish so much.

Since they are not using as much energy, the excess food, will sink to the bottom and produce waste and ammonia which can be deadly to your fish.

When your fish hibernate their bodies suppress their appetite to conserve energy.

In most cases, the fish will live through the winter months by eating little amounts of the natural growth of algae.


What To Do With Ice On My Pond

If you reside in a colder area and ice is beginning to form and you are unable to prevent it, you will need to make a purchase of a de-icer.

A de-icer will make a hole in the ice where oxygen can still flow in and out of the pond.

As the fish are hibernating they require little oxygen, so by having a de-icer, it will create a hole in the ice which ensures the fish have enough oxygen to survive the winter.

Another easy way to prevent ice from forming is to get a bubbler and place it at the bottom of your pond.

The bubbles that are produced from the machine will float to the top and create flow.

If you have flow in your pond it will be difficult for ice to form. Ice forms first in still areas and will later spread to the rest of the body of water.

If it is very cold in your area you may see thin layers of ice form on the edges of your pond.

By having the bubbler in the center of your pond it makes it nearly impossible for ice to cover the entire surface.

In the event your pond does completely ice over the bubbler will be producing oxygen bubbles in your pond.

If you wake with a complete layer of ice you will not have to worry as the bubbler will be producing oxygen for your fish.

If you wake up in the morning and find a layer of ice covering your pond the first thing you need to do is break up the ice and remove large chunks.

Once there is a layer of ice oxygen will not be able to be exchanged, meaning the oxygen in your pond will be used very quickly and have no way of getting more into the pond.

Once you have broken up the ice follow one of the steps of preventing ice from forming.

Keeping ice off your pond is not difficult and can save the lives of your fish.


What Happens As Water Gets Colder In Ponds?

As water temperatures begin to decrease during the winter, you’ll begin to notice your fish being not so active.

This is because they are trying to not use as much energy to stay warm during the winter.

During the winter months, fish’ heart rate slows, oxygen utilization will decrease and brain usage will be reduced.

Your fish will also not eat as much as well as them staying near the bottom of your pond.

Fish stay at the bottom because that is where water is the warmest, where they don’t have to spend much energy to survive winter.


How To Keep Your Plants From Dying In The Winter

How To Keep Your Plants From Dying In The Winter

During the winter like most other plants, they will hibernate and lose their leaves, or completely shut down to the roots.

If the temperature in your pond becomes too cold just like fish the plants can also die.

Plants need to have a good root system in order to survive winter as well as come back bigger and stronger in the spring.

If the temperature of the water gets too cold the plants will also start to shut off its root system to try and preserve energy.

If the plant shuts off too much of the root system it will cause the plant to die and come back in the spring.

By keeping the water warm you are not only keeping your fish safe, but you are also helping your plants survive the winter.


What Temperature Is Comfortable For Pond Fish?

If you have a pond full of goldfish, a good temperature range for them is around 65-74 degrees.

Goldfish are hardy, meaning they can withstand drastic temperature changes as long as it doesn’t occur too fast(overnight).

Koi, on the other hand, have a much greater temperature range from 60-78.

During the winter it is very common for these temperatures to drop well below the 60-degree mark.

When the water gets this cold your fish are still safe and will die due to the water temperature.

If you want your fish to stay healthy during the winter it is highly recommended that you heat your pond and try to keep it as warm as possible.

By keeping it ten or more degrees warmer will have a great impact on your pond in every way. Your pond will stay cleaner, your fish will be a little more active, and your plants will have a better chance of lasting the winter.


Help Beneficial Bacteria Stay Active

Once the water temperature in the pond starts to drop, so does the activity of everything else in your pond, even at the microscopic level.

Beneficial bacteria is the microscopic organism that helps break down and reduce sludge and debris.

Beneficial bacteria also help remove harmful chemicals such as ammonia in your pond.

When temperatures get cold it makes it harder to be active and the same goes for fish and beneficial bacteria.

When the bacteria in your ponds slow down it means more and more sludge and debris will build-up at the bottom of any pond.

If you do not properly treat this it can have major impacts on your pond over the summer.

When debris breaks down, it releases ammonia into the water, and if the bacteria is not active the ammonia level will easily reach out of the safe zone.

An easy way to ensure your pond stays clean during the winter is to add barley straw, the straw release chemicals to break down debris and also kills algae in the process.

I’ve written an entire article focused on barley straws if interested.



The winter months can be tough to handle, but if you’re prepared, it should not be a problem.

Even my doing just a few of these steps will make an enormous impact on the temperature and health of all aquatic life.

You should not spend a lot of money trying to keep your pond warm during the winter, all you have to do is follow these simple steps.