Ice on My Fish Pond: Dealing with a Frozen Water Feature

The first snowfall of the winter is exciting as we hideaway in our homes with a cup of hot chocolate watching the beautiful white snow blanket our yards.  We notice how pretty our water garden looks glittering with white but then panic sets in when we realize it’s frozen!  No need to panic. We’ve got you covered, here’s what you need to know if your pond freezes over. 

Assuming your pond entered winter in a healthy state, without a lot of leaves or debris on the bottom, and not overstocked with fish, everything should be okay.  If you have a shallow pond or shallow areas with pond equipment, check to make sure they haven’t frozen as well. We suggest removing your pond equipment at a water temperature of 40°F and installing a floating heater, a deicer, or an aerator. Leaving the pump running in cold temperatures could lower deep-water temperatures, causing potentially fatal fish stress. It also puts the equipment at risk of cracking. 

When a pond freezes, it forms what would best be defined as an ice cap. This ice cap will generally cover the surface of the pond but isn’t airtight and can still allow airflow. Ponds freeze from the top down and very rarely freeze solid all the way through. Cold water usually has a good amount of oxygen dissolved in it, and any fish or wildlife, lethargic in the cold, will be using up less oxygen. If this is the case, aquatic life should be able to cope with the surface being ice capped for a few days without being in any danger. However, if the surface stays completely sealed for more than a few days, problems might arise for any pond inhabitants. The oxygen levels can start to fall, and dissolved gases, like ammonia, may start to build up in the water. This is especially a problem when the pond is overloaded with fish, has a lot of debris on the bottom, or has snow on top of the ice. If there’s snow on top of the ice, try using a long-handled broom to clear the snow; noisy shoveling can be stressful to dormant fish.  Removing the snow will allow light to penetrate the pond for submerged plants to do their job, create oxygen.  

To allow for vital gas exchange, keeping a hole open in the ice is a good idea. But don’t break the ice. Breaking a hole in the ice can stress your fish, so try melting a hole instead. You can do this by pouring boiling water in the same spot on the ice at least twice a day. To prevent freezing altogether, use a small floating pond heater or a deicer. An aerator can also be used during the winter to keep an open area in the ice. Even if the pond freezes, aerators still de-gas the pond and move the pocket of air between the pond water and the ice cap. 

If your pond hasn’t frozen over yet and the forecast predicts icy weather, follow these preventative measures to keep your pond from distress: 

While a frozen pond can be a cause for concern, with proper preparation and monitoring, your pond fish should be able to safely weather the winter. By taking preventative measures like removing equipment at the appropriate water temperature and using de-icers or aerators, you can minimize the risk of damage to your pond and ensure the well-being of your aquatic life. Remember to check on your pond regularly, paying attention to signs of distress and taking action to maintain water quality and oxygen levels. With a little care, your pond can remain a beautiful and healthy ecosystem throughout the winter.