The winter koi pond is pretty but not very exciting. It’s generally a source of water for the little birds, squirrels and deer.  The sub-zero temperatures have threatened to ice over the pond a few times.  Just to be sure it didn’t completely close up, on the coldest days, we threw a few buckets of hot water on the ice to keep the ice formation in check. The koi stay huddled around a pond warmer at the bottom, pretty much oblivious to everything.