Pond De-icers and Heaters: survive tough winters keeping healthy fish

In the winter when cold weather chills the pond water, koi and goldfish must adapt to survive in this less than friendly environment. Being “cold-blooded”, their body temperature falls along with the water temperature. This decreases their breathing rate and energy needs.

My favorite de-icers are the Laguna and the Aquascape , keep on reading for more options!

If you can see through the ice, koi and goldfish either swim very slowly or don’t move at all in cold water. If your pond is home to frogs, they’ll burrow into the mud and leaves at the bottom and hibernate there over the winter. Amphibians able to do this by breathing through their skin.

However, if the pond’s surface is sealed with a layer or ice, especially with a cover of snow, it can cause “winterkill,” resulting in the death of fish, frogs, and other aquatic life. The good news is that a pond de-icer will prevent winterkill from occurring. But first, let’s take a closer look at what happens under the ice during the winter.

What happens under the ice during the winter?

How to protect your pond from winterkill

Pond de-icer FAQs

Can I heat my pond with a de-icer?

Will a de-icer keep my fish active all winter?

How large of a hole in the ice do I need?

Do de-icers use a lot of electricity?

Top-rated Pond De-icers

1. K&H Pet Products Thermo-Pond Heater

The K&H Thermo-Pond Heater is actually a de-icer.

It won’t heat the entire pond but it does stop ice from completely sealing the surface.

The de-icer has a unique, patented design that makes it one of the most popular pond de-icers.

The black floating 12-inch disc absorbs the sun’s heat and radiates it back into the water. But that’s not enough to keep the ice away. Inside the ring is a 100-watt heating element that provides continuous heat. Internal thermostats automatically turn the Thermo-Pond on and off as needed.

The patented technology promises that the pond de-icer will only run as often as needed to maintain a 12-inch hole in the ice. The 100-watt model is rates for ponds up to 1000 gallons. Larger sizes are available.


  • Small size is lightweight and easy to put in and take out of the pond.
  • Uses only 100 watts.
  • Won't burn the pond liner.
  • 12-foot power cord.
  • Simple, rugged design.
  • One-year warranty.


  • None.

2. TetraPond Pond 300-Watt De-Icer

The TetraPond de-icer is based on a 300-watt heating element imbedded inside a faux floating rock.

An internal thermostat controls the operation of the de-icer. This de-icer is recommended for ponds 300-gallons and larger. It has a 15-foot power cord.

Measures 10-1/2" x 5-1/2".


  • UL-listed.
  • 3-year warranty.
  • 15-foot power cord.


  • Unattractive fake rock shape.
  • Has some reliability issues.

3. Laguna Power Heat Heated De-Icer

The Power Heat de-icer is a fully-encased unit that floats on the pond surface.

The seven-inch diameter disc contains a 315-watt heating element that will keep an opening in the ice when temperatures down as low as 20 degrees Fahrenheit.

The Power Heat features a 15-watt heater embedded into the top of the dome to melt snow and keep the hole exposed to the air.

For added stability, the de-icer can be anchored to the pond bottom using a string or cord attached to the hook underneath the de-icer and weighted to the bottom of the pond by a brick or other suitable weight.

A thermostat prevents overheating if left plugged-in when out of water. It is safe for plastic and liner ponds. A LED light shows that the Power Heat is connected to an active power outlet.


  • Has a LED power indicator.
  • Includes a special element to melt snow.
  • 22-foot electrical cord.
  • Can be anchored if necessary.


  • None.

4. Aquascape 39000 Pond Heater and De-icer

This Aquascape floating pond de-icer is made of durable stainless steel.

The stainless-steel housing contains thermo-sensors that measure water temperature from different locations within the unit.

This smart technology allows for accurate thermostatic control even in freezing conditions.

A blue LED indicates the de-icer is plugged in. A red LED indicates the de-icer is heating. This allows you to visibly see if the unit is working.

The manufacturer rates this 300-watt heating unit for most locations in the US and Canada. The de-icer is safe for plastic and liner ponds. The unit comes with a 22-foot electrical cord with grounded plug.


  • Stainless steel construction prevents corrosion and cracking.
  • Integrated thermostat saves electricity.
  • Built-in LED light indicates de-icer status.
  • 22-feet power cord.
  • 3-year warranty.


  • None.

My Pick

All of these pond de-icers will keep your pond safe over the long winter months. The main differences are the size of the heating units inside the de-icer.

The K&K Thermo-Pond heater is the lowest-rated (100 watts) heating capacity but is a very popular de-icer. It is lightweight and has a long power cord. If you need more heating power due to extremely cold climates, a higher wattage de-ice is probably beneficial.

The Laguna Power Heat boasts 315 watts and a LED light that indicates that the heater is plugged in. It also has a dome heater to keep snow from covering the de-icer and open hole in the pond.

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