Do I Need a Pond Aerator This Winter?

If you have fish that you wish to winter over in your pond it’s necessary to use a pond aerator. A pond aerator or small recirculating pump that agitates the water’s surface will oxygenate the water. Why do you need to oxygenate your pond in winter? When people drown, their bodies are deprived of oxygen because their lungs fill with water rather than air. Fish obtain their oxygen from air that is dissolved in the water in which they swim. … Oxygen diffuses into the fish through their gills, without aeration your fish will drown! (Well…technically speaking suffocate may be a better term.)

If you don’t have fish in your pond a pond aerator can still be beneficial as it will help to continue to break down nutrients from leaves and debris in your pond and keep the water from becoming stagnant and foul smelling, but is not necessary.

Other options for winter aeration: a small recirculating pump may be used instead of an aerator. It will pump water up to the surface of the pond an agitate the surface (which adds oxygen to the water.)

A recirculating pump such as the one pictured above can be used to provide necessary oxygen to your pond in winter in place of an aerator.

Pond Aerators provide oxygen to your pond in winter and are necessary for keeping fish alive through the winter

Will a pond aerator alone keep my fish alive in winter?
No.  An aerator adds oxygen to the water.   If the temperatures drop you still need to be able to maintain a hole in the surface of the ice for gas exchange.   What is gas exchange?  Your pond slows down over the winter months, but it never completely shuts down. Leaves and debris continue to break down  too,  just at a slower pace than during warmer months.  The process of the plants and debris breaking down creates methane gas.  When the ice is allowed to completely cover the surface of the pond methane gas builds up and harms the aquatic life in your pond -including your fish.  To prevent this use a simple deicer.  The better ones are thermostatically controlled so that they consume electricity only when the temperatures drop.  The deicer keeps just a small ring around the unit melted in the ice and allows the harmful gasses to escape.  When installing a deicer for the winter be certain that it is placed a good distance from the aerator as the movement of water by the aerator may make it run more often than necessary.

De-icers keep a small hole in the ice allowing for gas exchange in Winter.