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What to do if your pond freezes over

Winter is a great time of the year; but what does it mean for your pond? What should you do if your pond freezes over?

29 November 2021

how to keep a pond from freezing without electricityWinter is an exciting time of the year. Snow, hot chocolate, Christmas music, family and friends all contribute to a wonderful time of the year. But what does winter mean for your pond? Will your pond freeze over? We have you covered, so don’t worry.

When your pond freezes over, the ice on the surface forms an 'ice cap'; as this spreads over your pond, in most circumstances, it will still allow gasses to be exchanged. Oxygen will still be absorbed from the air and Ammonia will still be released; this process will just be slowed down. Assuming your pond is in a healthy state before it freezes over, everything should be ok. If your pond is ornamental with no fish, you don’t have to do anything to your pond unless you feel the need to do so.

Cold water usually has a good amount of oxygen dissolved in it, and any fish and wildlife 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. However, if the surface stays completely sealed for more than a few days, you will need to act.

What happens when your pond freezes over?

The oxygen levels may start to fall, and gases may build up in the water. This could be a deadly combination and will prove to be fatal to your aquatic life, especially for a heavily stocked pond; where there is a lot of debris in the pond; or has snow lying on the ice, stopping light from reaching underwater plants. 

Step 1 – Remove Snow: Use a standard brush to remove the snow, as noisy methods can disrupt the hibernating fish.  This will allow light to reach your aquatic plants, enabling them to oxygenate your pond. 
Step 2 – Make a hole in the ice: While being as quiet as possible to avoid disturbing your fish, try melting a hole in the ice by placing a pan with boiling water onto the ice; this helps to melt it slowly without affecting the fish.

Some people will pour boiling water onto the ice; while this may work, can heat the temperature of the pond up and disturb your fish. So avoid pouring too much boiling water onto the ice. Never use a hammer and chisel to break a hole into the ice. This can send shockwaves throughout the pond due to the pressure underneath the ice; this can stress your fish out and potentially kill them.

Winterizing Ponds and Water Features - Garden Fundamentals

How to prevent your pond from freezing over

There are several methods which can prevent a pond from freezing over.
1. Keep your Pump running – This circulates the water and prevents ice forming. Try to keep the pump away from fish and below the ice levels of your pond. You do not need to filter your water as waste is at a minimum during winter.
2. Keep an aerator turned on – The air pump displaces water and forces it to move, preventing the surface from icing over. Just like a normal pump. Air pumps are great; we recommend them as one of our 5 Tips Which Can Make A Big Difference To Your Pond. On the benefits of aeration, please see our blog posts.
3. Get a De-Icer – These are often small, floating heaters which keep the water hot enough to prevent ice from forming.

Turn off equipment

If you are expecting icy weather, turn off your fountains and ornaments to prevent your water features from freezing up as this can cause water loss. Once the ice has melted, if the pond has an odour (like a stale smell) then do a partial water change and use a dechlorinator

If you need any further assistance, please email us on

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