How to Keep an Outdoor Fish Pond Warm for Winter

Maintaining your fish pond over winter might require heat.

You can keep a fish pond warm as temperatures drop during winter by adding heat. Covering and protecting the pond adds a layer of insulation and further protection. If your pond is shallow, your fish will likely need some help to survive the winter freeze.

Things You'll Need

• Pond heater
• Four 2-by-4's
• Nails
• Hammer
• Plywood
• Stryofoam or straw
• Plastic sheeting or tarp

Instructions

1. Purchase a heater designed specifically for fish ponds. A standard heater is submersible and puts out 1250 watts or more but others use as little as 100 watts. The heater allows a small pond to remain ice-free or will make a hole in a larger pond that allows air exchange, helping fish survive. Most have been tested down to -10 degrees Fahrenheit. Outdoor pond heaters have efficiency settings to operate only when the water temperature approaches freezing.

2. Submerge the pond heater. Make sure the heater is placed in the deepest part of the pond. This will distribute the heat thoroughly.

3. Construct a frame to provide support to cover the pond. Covering the pond will prevent exposure to extreme weather and cold. Used in addition to the heat pump, this will significantly reduce the amount of electricity used. Build a wooden frame high enough to leave space above the surface of the water when the frame is covered. Use 2-by-4s and nail them together to form a square or rectangle. Be sure the structural frame you build is strong enough to support the anticipated accumulation of snow.

4. Cover the wooden frame with plywood and nail it in place. The plywood should be up above the surface to permit the easy exchange of gasses, which also permits the proper insulating layer of air as a cushion of warmth. Add insulation such as Styrofoam, mulch or straw.

5. Add a layer of plastic or a tarp as the final layer of protection for your fish pond.

Tips & Warnings

• Don't try to break through ice after it has formed on a pond. The shock can kill overwintering fish.

• Stop feeding fish as the temperature gets colder.

• In shallow ponds fish need extra heat or help to make it through the winter. In ponds of 7 to 8 feet in depth, fish will survive winter temperatures.

References

• Aquatics Unlimited: Winter Care Guide for Garden Ponds
• Aqua Articles: Your Pond in Winter
• Pond-O-Mania: Pond Heaters
• Garden Ponds 101: Pond Heaters

Resources

• ABCPonds: Fish Pond Winter Maintenance
• Greg Robert: Thermo-Pond Pond Heater
• Backyard Birds: Bird Bath Fisth Pond Heater