Question
We live in mid Missouri.  Winter temps get down to zero or below.  We have a 1500-2000 gallon, lined fish pond in the garden.  (cement with a rubber lining)  We have been told that the koi can live in the pond thru the winter.   Is this true?   What precautions should we take?   What about feeding?   Aeration?   Should we use a floating de-icer unit?   Thanks for any help or insight you can provide.  Lew Leake  

Answer
It depends.  How deep is the pond?  Is it heated or does it have a de-icer at least?  If you can keep an opening in the ice and prevent the pond from freezing to the bottom, the fish can overwinter in the pond.  Do not feed them when the water temperature is below 55 degrees F.  Putting an air stone on the bottom (below the de-icer helps) is a good idea to be sure that the fish get oxygen down there and let out carbon dioxide.  A floating de-icer is a good idea.  See my winterizing page at http://www.fishpondinfo.com/winter.htm for a lot more on keeping a pond going in the winter.  You are in a much colder area than here in MD so I do not suggest running any waterfalls, etc.  Good luck!