How to Use Aquarium Heaters for Ponds

Outdoor fish ponds add character and color to any backyard garden. Most of the time, outdoor fish do not have special requirements for water temperature.However, in areas where the temperatures drop below freezing regularly and for prolonged periods, aquarium heaters will prevent ice formation. While most pond fish can tolerate water where the surface has frozen, they risk death if the pond freezes completely.

Things You'll Need

  • Garden hose
  • 1 gallon container
  • Aquarium heater (submersible or conventional)
  • Pond Deicer (optional)
  • Small dowel rods
  • Finishing nails or wood glue
Show More

Instructions

    • 1

      Calculate the volume of water in your pond. It is important to know how much water you are attempting to heat to purchase the correct size heater. An easy way to tell how much water your pond will hold is to use a water hose and a timer. Fill a 1-gallon container with water from a hose. Measure the length of time it takes to fill the container. Then insert the hose into the pond and measure the length of time it takes to fill the pond. Divide the time it takes to fill the pond by the time it took to fill the gallon container. The result is the number of gallons in your pond.

    • 2

      Purchase an aquarium heater for this volume of water. Depending on the size of your pond, you may need to buy more than one heater.

    • 3

      Install the heater. A basic aquarium heater is not going to attach directly to the pond walls. You will need to build a wooden or metal apparatus to hold the heater in the correct upright position. Use small dowel rods and finishing nails.Keep the very top of the heater out of the water, unless you purchase a fully submersible heater. If the latter is the case, you can simply place the heater directly on the bottom of the pond. If you choose to use a submersible heater, you should use it in tandem with a surface deicer so that toxic gases can escape.

    • 4

      Set the temperature on low, preferably a few degrees above freezing, and plug it into a power source. The goal is to keep the pond from freezing over, not to keep the pond at a specific, uniform temperature throughout the winter.