Keeping a hole in the ice that forms on the surface of your pond is essential for the life of your koi and pond fish during winter. A pond deicer, some people call a pond heater, is designed to keep a portion of the surface from freezing to allow toxic gases and oxygen to exchange in the water. Each unit is designed to only use energy when it is needed.
We strongly recommend that a pond de-icer be used with an aeration system, especially if you have fish larger than 8 inches. The combination of both make for very happy and healthy fish!