Aerating your pond in the winter time is useful at keeping ice from forming at the surface. It’s crucial that fish get adequate oxygen from the atmosphere, even in colder weather, so keeping a spot of ice open is very useful.
You can use a pond heater of course, but many people also like, and might even prefer a small pond aerator to do the job. Some advantages are they can use the device year round, and they usually cost less to operate than a heater.
But there are potential challenges with them.
First, just like an electric heater, if your power goes out, you may find that your pond can freeze over pretty quickly. You can often get around this with a small generator.
The other issue we see from time to time is that ice can form in the airline and block airflow to the pond. This happens because condensation forms in the airline, and once it’s cold enough it will freeze. Initially, the problem is that you’re not getting any air or agitation into the pond, but if this goes on long enough, damage could occur in the pump itself. Usually the diaphragm will be damaged and would need to be replaced.
So for consistent, day to day operation, the best option is to avoid or limit condensation build up in the first place. Sometimes this is difficult to do, but as a general rule, we like to suggest that the compressor or pump be kept either indoors, or within some kind of insulated enclosure. The pumps do produce some heat, but when the outside temperature is very cold, they shouldn’t overheat, and you’ll want to limit the exposure to the cold air and moisture in the environment.
Keeping the compressor warmer, and hopefully drier than the outside air should be helpful.
Also, if your airline runs over open ground for a bit, consider putting some kind of insulating cover over it. Hay or straw, piled over it may help, as could any type of insulating material (pipe insulation works well here too). Once the airline reaches the water and becomes submerged the likelihood of freeze up will drop.
As a back up to an aerator, if you live in a really cold climate, it’s not a bad idea to use a pond heater, on a limited basis when the weather dictates. Most of these won’t turn on until the water actually starts to freeze so they’ll be less costly to run, and may help keep a pond open, when an aerator may not keep up for some reason.
Finally, if you do find that you pond is covered with ice. Avoid the temptation to pound, hammer, or chip away at the ice. This can create shock waves that can stress or harm fish. We advise taking a back or bucket of hot water and either setting this on the ice in order to thaw a spot, or you might try pouring hot water over a small area and see if you can get the ice to open up that way.
In most cases, pond aerators will run trouble free through a variety of conditions, including cold weather. But with all mechanical things, problems can come up, and being prepared, or simply trying to prevent a few issues can keep your fish safe throughout the winter months.