How To Winterize A Pond With Fish

Nick Durante
by Nick Durante

There are many things to take care of on your property before winter hits, and it can be stressful. It can be intimidating if you have never winterized a pond with fish, but it’s necessary. Whether you’re new to ponds or have years of experience, you may still struggle with how to winterize a pond with fish.

The first step to winterizing a pond with fish is to thoroughly clean it, remove debris, and trim the plants. Next, you must perform a water change and replace 20%-30% of the water with fresh water. Add enzymes and non-iodized salt to the water, and switch to feeding your fish wheat germ-based food so they can adapt to the slower metabolism before winter.

Use a pond de-icer if you live in a harsh climate where water typically freezes during winter. Make sure to clean your filter and pump and remove the excess water so the fish don’t freeze when it’s cold. Follow along as we explore in just 10 steps how to winterize a pond with fish.

Can You Leave Fish In A Pond Over The Winter?

You can leave fish in a pond during the winter. Fish typically make their way to the bottom of a pond during the winter. That is because the pond floor is usually warmer than the rest of the water.

Fish become dormant during winter, but they can be kept alive under the right conditions. They lower their heartbeat, they become mostly inactive, and their metabolism slows down. Once the temperature returns to the low 50s or higher, fish in a pond will become active again.

How Do You Close A Pond For The Winter With Fish?

1. Deep Cleaning

You must thoroughly clean your pond before you close it for the winter. If you don’t clean the pond before you close it, bacteria and even toxic gases can harm the fish and they won’t likely survive. It is recommended to use a pond rake to scrub the floor and walls of the pond.

This helps to remove algae and muck that may contain bacteria and discolor the pond water. You can also use a net to pull debris and fallen leaves out of the pond. Failure to remove muck and debris from the pond will make it much more difficult to open the pond in the spring. Organic matter continues to break down in your pond even during the winter, so you will find a big mess in the spring if you don’t clean it well.

2. Change The Water

Before you treat the water, you must perform a water change. Change out between 20% and 30% of the water. It will be much easier to treat the water with enzymes and bacteria if a good portion of it is fresh.

Simply use a pond vacuum to pump out up to 30% of the water and use a hose to replace it with fresh water. Gradually perform the water change so you don’t disturb the fish.

3. Add Enzymes

Once you’ve removed debris from the pond, it’s time to treat the water. Add 25% more non-iodized salt to the water. This will protect the fish and help reduce algae growth throughout the winter.

Next, I recommend that you treat the water with an enzyme cleaner. Enzyme cleaners like WinterKleen feature a mixture of enzymes and healthy bacteria that promote a safe environment for fish during the winter. The fish may lay dormant throughout the winter, but the presence of healthy enzymes and bacteria can keep them safe. These enzymes also break down pond sludge, as leftover debris degrades and turns into sludge throughout winter.

4. Trim The Plants

Overgrown plants are bad for your pond during the fall and winter. The excess foliage and leaves will likely die and break down within the pond. This can contribute to sludge forming, and that’s the last thing you want when the water is too cold to clean.

Remove any struggling plants that are already in bad shape, because they won’t likely survive the winter. Using long shears, trim healthy plants and collect the trimmings with a pond rake or net.

5. Clean The Filter

You must clean your filter and remove it when you winterize your pond. Thoroughly clean the bio balls and filter pads by hand, then rinse them with a hose. Pay attention to your filter’s condition and replace any parts that are damaged or don’t work well.

Let your filter dry, then store it in an airtight container. Ideally, you should store your filter indoors throughout the winter, so it stays at room temperature. You can bring your filter back out and reinstall it when spring starts.

6. Take Care Of The Fish

You need to give the fish as much attention as possible before you winterize the pond. First, you must switch up their diet and feed them autumn food. Autumn food is different from standard fish food in that it doesn’t have quite as much protein.

Instead, it features wheat germ, which helps their metabolism adapt and slow down. This is important because their metabolism will naturally slow down when the temperatures drop. Changing their diet helps ease them into this transition to make them more comfortable and ensure they get as many nutrients as possible.

Look for autumn fish food that contains lots of vitamin C. Closely monitor the temperature as it gets cooler throughout autumn. Make sure to stop feeding your fish once the temperature drops to the mid-50s. Once it gets too cold, they won’t be able to properly metabolize the food and it can harm them.

7. Help The Frogs

Your pond likely attracts lots of frogs. During the winter, frogs need a safe place to burrow and protect themselves from the cold weather. Fill a bucket with sand, clay, or a mixture of them both. Lower it to the floor of your pond and make sure it sits evenly. If it’s heavy enough, the sand and clay will form a dense bond and most of it will stay in the container. Frogs can use the bucket to burrow in and sit dormant and be protected during the winter.

8. Install A Pond De-Icer

This is an optional step, but I recommend using a pond de-icer to protect your fish when you winterize your pond. Pond de-icers are especially necessary if you live in a climate with harsh winters, such as the East Coast or the Midwest.

These small devices ensure that there will at least be a single opening in the ice if your pond freezes over.

This will prevent your fish from suffocating and dying when the pond freezes. You may not need a de-icer if you don’t expect lots of snow and ice, but it is nice to keep one around as a backup. Use a few pond de-icers if your pond typically freezes several times each winter.

9. Deactivate The Pump

You must deactivate your pond pump before you finally close the pond for the winter. Shut off the pump’s power and carefully pool it out. Make sure to empty any water that remains within the pump.

This may take some time, but you can use tubing to quickly get rid of the excess water. If you don’t remove the water, the pump may freeze during the winter, and this could break many of the key components. Pond pumps can cost anywhere from $50 to $5,000, so the last thing you want to do is rush to buy a new one when spring comes around.

10. Install Netting

Netting is essential to protect your pond from fallen leaves and debris. Without a net, debris can easily fall into your pond, degrade, and eventually form sludge and feed bad bacteria. This creates an unhealthy environment for the plants and fish in your pond.

Wait to install your net until after you have treated the water, trimmed back the plants, cleaned the filter, and changed the water. This should be your last step. Use netting with a PVC frame so you can easily stake it into the ground and make sure it doesn’t blow away.

Summing It Up

Make sure to clean the pond with a rake and net to remove debris and sludge. Add 20%-30% fresh water to the pond and use enzymes to reduce algae before winter. Feed your fish food with wheat germ and stop feeding them when the temperatures reach the mid-50s.

Use a pond de-icer if you expect your pond to freeze. This will let your fish get oxygen even if most of the pond’s surface freezes. Finally, you must add netting to keep leaves and debris out of the water during winter.

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Nick Durante
Nick Durante

Nick Durante is a professional writer with a primary focus on home improvement. When he is not writing about home improvement or taking on projects around the house, he likes to read and create art. He is always looking towards the newest trends in home improvement.

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