Do You Need a Pond Deicer? Here’s the Truth

Last update:

Sharing is caring!

There is nothing better than looking out at a frozen pond in your yard. However, you may want to keep a pond deicer nearby just in case. Here’s why.

You will want to use a pond deicer in the winter because a completely frozen-over pond will not allow any oxygen into the water, which can suffocate your fish. It also won’t allow for the release of any harmful gasses that might be the result of fish waste and respiration.

Read on for a few helpful reasons why you might want a pond deicer on hand.

What Does It Do and Why?

Not to be confused with a pond heater, a pond deicer is a small device that floats on the surface of your pond. During the winter, it will keep a small hole in the ice so your fish can come up to breathe. The deicer will also allow for the escape of toxic gasses. These come from decaying organic materials, and exhaling fish. This is another way your fish could suffocate if they do not get enough clean oxygen.

Not only will a pond deicer come in handy for keeping your fish alive, but it will also improve the health and cleanliness of your pond. Gasses trapped underneath the ice can not only kill your aquatic wildlife but they will probably give off foul odors as well, and nobody wants to encounter that in the spring.

Remember, do not confuse a deicer with a heater! They are two different products that achieve two very different things. A deicer will melt holes in the ice over your pond, but a heater is actually used to increase the pond’s temperature. When using a pond heater be careful. It might be fine to increase the water temperature but doing so can be dangerous for your fish so use caution.

How to Use One

Note: obviously you can create your own holes by simply smashing through the ice with a shovel or axe. This is a BAD IDEA. It may be cheaper than purchasing and setting up a deicer but it can create shock waves that will either kill or cause brain damage to your fish. A pond deicer is a much safer choice.

One deicer will suffice for a 600 gallon pond. If your pond exceeds 600 gallons, you will want to utilize two or three deicers tied together. Plugging the deicer into an extension cord works, but it could actually limit effectiveness which is why you will probably want to opt for an outlet installed right next to the pond.

Obviously for some people this is not practical. Using an extension cord is okay, just make sure it is as short as possible.

It is a good idea to put your deicer as close as possible to the pond liner. This will spread heat more quickly and effectively throughout the pond without harming the fish. However, you will want to double check whether or not the deicer can touch the liner. If it is too strong, it could melt the liner and cause a leak in the pond.

You should put a floating or submersible deicer in the shallowest area of the pond, but make sure you block floating ones from the wind as much as possible. Wind will steal heat faster than the deicer can make it, so put it in a sheltered area where the heat will all go to the pond. If needed, you can even put a sheet of plywood over the top of the deicer to keep the wind from affecting it.

Do not cover the entire pond, however. Doing so can prevent the needed gas exchange.

It is not a good idea to put a deicer right into an already frozen pond, especially if the ice is thick. If you are not able to get one installed before winter comes, boil a pot of water and very carefully pour it over a spot in the ice. This will melt a hole for you to put the deicer in without damaging it or your fish.

Types of Deicers

As with a pond pump, you will want to choose the right deicer that will best serve your needs and do its job right. You should make your decision based off how many gallons your pond holds, as well as whether you are using an aeration system in addition to the deicer.

For a 250 gallon pond or less, a 100 watt deicer will suit your needs just fine. For 500-1,000 gallons, a 750 watt, for 1,000 to 1,500 gallons a 1,250 watt, and for 1,500 to 2,000 gallons, a 1,500 watt deicer and so on.

To help you get started in your search for a good deicer, here are four models you might want to take a look at.

The K&H Thermo Pond 100 watt deicer. This deicer is 12 inches long with an internal thermostat that will turn it on and off automatically when needed. It will not heat/melt all the ice in the pond, but it will keep a small hole unfrozen so your fish can breathe. It is small, easy to install and uninstall, and has a 12 foot cord and one-year warranty.

The TetraPond deicer has a 300 watt heating element and is embedded inside a faux rock. It has a 15 foot cord, is UL listed, and has a three-year warranty. The only cons are that the rock shape can be unattractive in the wrong pond and it has a few more reliability issues than others.

The Laguna Power Heat deicer. This device is a fully encased, floating deicer. It has 315 watts and can keep a hole open in as low as 20 degree weather. In addition, there is a 15 watt element built into the top of the dome that will melt snow as well as ice. A few of its features include an LED indicator light, and a 22 foot cord. It is safe for all pond liners and can be anchored to the pond floor if necessary.

The Aquascape 39000 Pond Heater and Deicer. This deicer is made of durable stainless steel. It has built-in thermo-sensors that monitor water temperature in several locations within the unit. A few of its features include a built-in LED indicator, integrated thermostat, and a 22 foot power cord. It has a three-year warranty.

Maintenance and Troubleshooting

As with any other pond device, you will want to take good care of your deicer. There can be mineral buildup on most deicers which then prevents them from working properly and can even cause premature failure. To avoid this, inspect the heating element often and clean it regularly with water. If the buildup is too great, it may require you to purchase and use a limescale remover.

You can also use Lime-away or vinegar to give it a quick polish. The cleaner your deicer is, the more efficiently it will work.

If your deicer quits or malfunctions, here are a few things you can try. First, check the LED indicator light to see if it’s working (not all deicers have one of these but most of them do). If the LED light is red, that means the deicer is in heating mode. If the light is blue, that means it is in off mode. If it will not turn on, maybe take it in to get looked at.

Before jumping to conclusions, however, check to make sure it is plugged in all the way. You can also check to make sure the ground fault interrupter or GFI rated receptacle are functioning properly.

The LED light is there as a safety precaution to prevent burns. If the LED stops working or the thermostat stops working, you may need to unplug it for a while and give it an hour or so to cool off completely. This will give the internal thermostat a chance to reset. There is also a chance that the deicer is not sheltered properly from the wind.

The wind will steal the heat off the device which prevents it from melting the ice so make sure your deicer is blocked from the wind. As said before, you can lay a sheet of plywood over the deicer, just as long as you do not cover the entire surface of the pond. It’s not healthy for your fish.

Using an extension cord is not recommended and can also lead to a dysfunctional deicer. It can lead to a loss of voltage if the deicer is not connected directly to the power source. If you are using an extension cord, try using a shorter one. If that does not work, consider investing in an outlet that can be installed right next to your pond. Sure it’ll cost more money up front but in the long run it will save you lots.

If all else fails, you might simply have to look into getting a new deicer. As with all things, it will require replacement from time to time. A good deicer, if used properly and well maintained, can last for several years. However, if it is poorly maintained, its life expectancy will become much shorter.

Photo of author


We always wanted a fountain of some kind at our house, but professional installation was just too pricey. So, we decided to make our own little fountain and after learning how, we thought we should share our experiences to help people in our same situation.

Leave a Comment