Q: Do I need to heat the water in my pond in order for my fish to survive the winter?
Kimberly – Bradford, PA
A: We all love central heating or a roaring fireplace in our homes when winter’s chilly temperatures roll in, but your pond fish—specifically your koi and common goldfish—don’t need those creature comforts to stay happy and content.
Cold Temps and Torpor
During the winter months when the water temperature is 45 to 50 degrees Fahrenheit and below, koi and goldfish enter into a dormant state. The technical term for this is torpor, and it means that the fishes’ metabolism and activity slows, they become very lethargic, and they require little nourishment. In this state, the koi and goldfish will, in fact, be quite comfortable in temperatures as low as 35 degrees.
These tools of the trade aren’t intended to turn up the heat in your pond’s water. They’re designed to simply melt a hole in the ice, which allows dangerous gases to escape while letting fresh and life-sustaining oxygen. When plugged into the Thermo Cube® Thermostatically Controlled Outlet, the de-icers will turn on when temps dip to 35 degrees and off when temps rise to 45 degrees on their own. To save even more on energy costs this winter, consider installing a PondAir™ & Thermo-Pond 3.0 aeration and pond de-icer combo. When used with an aeration system, you can use a lower wattage de-icer which will not need to be ran as often to maintain an open ventilation hole.
But the one thing de-icers don’t do: actively circulate or move the water like an aeration system does. That agitating action is necessary to trap and bring oxygen into the pond’s entire water column—including the bottom, where the fishes are snoozing. It also helps to prevent ice from forming a complete sheet on the pond surface.
Though running a pump will help move the water, it doesn’t agitate it enough to get those O2 levels up. A pump also costs more to operate than an aeration system, and, if ice does form, you could do some major damage to the unit from poor water flow. If you do not yet own an aeration system for your water garden, the PondAir™ & Thermo-Pond 3.0 Combo is a surefire way to protect your fish this winter.
Pond Talk: How do you keep a hole in the ice on your pond or water garden during the winter?