Best Pond De-icer for Koi Ponds in 2021: Reviews & Costs

Looking for a new pond de-icer or pond heater for your koi pond  this year?

You’re not alone.

We talk to pond owners every winter who worry their fish will suffer if they don’t have a pond de-icer or pond heater. We also talk to a fair number who recently purchased de-icers from farm supply stores, but already need a replacement because the one they just bought no longer works.

Sound like you? We have some good news. First, you don’t actually need a pond heater or pond de-icer! (more on that later). Second, if you like the peace of mind of having a de-icer, but don’t want to buy a new one every year, you can invest in models that will actually hold up.

Below, we’ll talk a little about what a de-icer does – and does not – do for your pond. Then, we’ll take a look at a few popular brands and compare them.

At a Glance: The Best Pond De-icer/Pond Heater for Koi Ponds and Goldfish Ponds (2021)

  • The best de-icer for koi ponds on the market today is the 300-watt pond de-icer from Aquascape. We like the durable stainless steel construction, energy-saving thermostatic controls and the three-year warranty.
  • But a de-icer on its own won’t be enough to create good gas exchange in the pond. For that, you need an aerator, which will actually break the surface tension of the water and let bad gases escape. You can often use an aerator instead of a de-icer.
  • If you still like the peace of mind of a de-icer, use the de-icer in addition to – and never in place of – the aerator. Place the de-icer over top of the aeration diffuser in the pond.

What is a Pond De-icer? And Do I Actually Need One?

A pond de-icer is a device that keeps a hole open in winter ice. It only heats the area immediately around it, and does not affect the overall temperature of the water or prevent ice from forming elsewhere in the pond.

(Many pond owners also refer to these devices as pond heaters – which isn’t completely accurate. A true pond heater would make the entire pond warmer, which isn’t necessary or healthy for your average backyard pond.)

To understand the allure of the pond de-icer, we need to talk a little about what our finned friends do all winter. While we’re nestled in our heated houses under comfy blankets, most pond fish – koi, goldfish, etc. – are going into a semi-dormant state called torpor that lets them survive the winter outdoors.

In this state, their metabolisms slow, they stop eating and they don’t move around much. They do, however, keep breathing. That means they not only need dissolved oxygen in the water, but the carbon dioxide they exhale needs a way to escape from the iced-over pond.

That’s where many pond owners turn to pond de-icers. The idea is that the de-icer keeps just enough of a hole open in the ice to let bad gases out and good gases in.

It’s a good idea, in theory. In reality, pond de-icers on their own actually do a poor job of promoting gas exchange in the pond. While they will keep a hole open in the ice, they don’t do much to break the surface tension of the water, meaning a lot of the carbon dioxide in the pond stays trapped.

Using an Aerator Instead of – or in Addition to – a De-Icer

Koi Pond AeratorOur first recommendation when pond owners ask for de-icers is to try an aerator first. The aerator – with a diffuser placed about a foot below the water’s surface – will push out a constant stream of bubbles that break the surface tension of the water, prevent ice from forming and add some much-needed dissolved oxygen back into the pond.

Unlike a de-icer, your aerator can stay in the pond year-round to keep fish happy and healthy. This is especially important during hot summers, when water has a hard time holding oxygen.

So why bother with a pond de-icer at all? 

If you live in a mild climate, you can likely skip the de-icer all together and use an aerator instead. In very cold weather, though, the de-icer can provide additional peace of mind when the temperature is too low for the aerator alone to keep a hole open in the ice. A de-icer can also serve as an emergency backup in case the aerator fails.

If you choose to use a pond de-icer, only use it in addition to – and not in place of – an aerator.

We like the Pro Air 20 aeration kit for ponds under 5,000 gallons, and the Pro Air 60 for ponds 5,000 to 10,000 gallons.

Comparing the 5 Most Popular Pond De-icers

Aquascape Pond De-icerTetraPond De-icerFarm Innovators Pond De-icerK&H Pet Products Pond De-icerLaguna Power Heat
Wattage300 Watts300 Watts1,250 Watts100 Watts315 Watts
Primary MaterialStainless SteelPlasticAluminumPlasticPlastic
Warranty3 Years3 Years3 Years1 Year1 Year
Thermostatic Control
Temperature Indicator Light---
Power Cord Length22 Feet15 Feet10 Feet12 Feet22 Feet
Winter Operating Cost$78$78$324$26$82
Price$149.98$47.15$47.64$45.99$79.99

OUR PICK

The Aquascape Stainless Steel Pond De-icer

  • POWER: 300 Watts
  • MATERIAL: Stainless Steel
  • WARRANTY: 3 Years
  • CORD LENGTH: 22 Feet
  • OPERATING COST: About $78 for three months of continuous use
  • OTHER NOTABLE FEATURES: Includes thermostatic controls and red/blue heating indicator light
  • PRICE: $149.98

If you decide to use a de-icer in addition to your aerator, our favorite by a long shot is the Aquascape Pond De-icer. While it’s the most expensive de-icer on our list, you’ll save money in the long run thanks to its durable construction, energy efficiency and 3-year warranty.

This de-icer features a stainless steel body that helps it hold up longer than its mostly plastic competition. If something does go wrong, you can easily get a replacement thanks to the warranty.

The 300-watt unit strikes a perfect balance between power and energy efficiency – strong enough for most winters, but not so powerful that it will run your electric bill through the roof. Thermostatic controls ensure the de-icer is only running when it needs to for additional safety and efficiency.

This model also has a highly visible LED that glows red when the unit is heating and blue when it’s plugged in but dormant. The ample 22-foot cord is another bonus for anyone who’s ever struggled to bridge the gap between their pond and electrical outlet.

Full disclosure: Aquascape’s Pond De-icer is the only one we sell in our store – but that’s only because we truly believe it’s the best one available.

TetraPond De-icer

  • POWER: 300 Watts
  • MATERIAL: Plastic
  • WARRANTY: 3 Years
  • CORD LENGTH: 15 Feet
  • OPERATING COST: About $78 for three months of continuous use
  • OTHER NOTABLE FEATURES: Thermostatically controlled, rocklike appearance
  • PRICE: $47.15

From the manufacturer:

“The TetraPond De-Icer helps release harmful pond gases by keeping an area of the pond ice-free. It features include a natural stone finish that blends in with your ponds surroundings. This product is 300 watts. Energy-efficient thermostat control shuts off power when not needed. UL listed. Effective to – 20°F (-28.8°C).”

Farm Innovators Pond De-icer

  • POWER: 1,250 Watts
  • MATERIAL: Aluminum
  • WARRANTY: 3 Years
  • CORD LENGTH: 10 Feet
  • OPERATING COST: About $82 for three months of continuous use
  • OTHER NOTABLE FEATURES: Thermostatically controlled, LED indicates when unit is heating
  • PRICE: $79.99

From the manufacturer:

“A virtually indestructible cast aluminum body houses the powerful 1,250 watt heating element which quickly opens a hole in the surface of your pond allowing harmful gases to escape. The Farm Innovators Floating Pond Deicer is thermostatically controlled and turns on only when temperatures drop below 35°F. The Farm Innovators Floating Pond De-Icer comes with a 10′ power cord and is safe for rubber and plastic liners.”

K&H Pet Products Pond De-icer

  • POWER: 100 Watts
  • MATERIAL: Plastic
  • WARRANTY: 1 Year
  • CORD LENGTH: 12 Feet
  • OPERATING COST: About $26 for three months of continuous use
  • OTHER NOTABLE FEATURES: Thermostatically controlled, unique design that absorbs the sun’s heat
  • PRICE: $45.99

From the manufacturer:

“The K&H Thermo-Pond 3.0 De-icer naturally allows the pond to freeze over while maintaining a 3″ ventilation hole to allow proper gas exchange to help fish survive the winter. The patented technology features a fully encased heating element that prevents damage to fish and rubber EPDM pond liners. Using only 100 watts and the internal thermostatic control, this de-icer will only run as often as needed to maintain a 12″ hole in the ice around the unit to save on energy costs, even in sub-zero weather. Ideal for ponds up to 1000 gallons.”

Laguna Power Heat

  • POWER: 315 Watts
  • MATERIAL: Plastic
  • WARRANTY: 1 Year
  • CORD LENGTH: 22 Feet
  • OPERATING COST: About $82 for three months of continuous use
  • OTHER NOTABLE FEATURES: Thermostatically controlled, LED indicates when unit is heating
  • PRICE: $79.99

From the manufacturer:

“The Laguna PowerHeat 315-watt De-Icer keeps and maintains a thawed, open area at the pond surface, allowing toxic gases from fish respiration and decomposing organic matter to escape. The thawed area also allows oxygen to re-enter the pond. Safe for plastic and liner ponds, the De-Icer will not harm fish or plants. The unit includes a highly visible LED pilot light that indicates when it’s on, a 15-watt heating element that melts snowfall on contact allowing clear visibility of the LED light, a thermostatically-controlled on/off feature that prevents overheating and saves energy costs, and a 22 ft electrical cord with grounded plug.”