Pond Heater ! It works.

Going into this winter, we were not sure what we were going to do to keep the Koi and Shubunken from turning into frozen fish sticks. Our pond is only 14 - 16 inches deep to it will freeze through if the temperature drops low and long enough. Andrew's son offered to keep the fish in an indoor aquarium for the winter (which was a very generous offer but likely a lot of work for them). Before taking him up on that offer, we decided to try a pond heater (it is the green circle in the picture). This heater kicks in when the water temp approaches freezing. I am happy to report that through several periods of sub freezing temps along with snow, ice and sleet, the heater is working really well. The pond is still cold (so the fish still stay in their lower metabolism winter mode) but has not freezed over.