OK I have 3 Koi fish and all are about 3-4 inches long.I have had them in an aquarium so they havent reached thier full potential.My question is..I live in Michigan and of course the water freezes here.My neighbor has a small pond maybe 1/2 acre in size.Does anyone think that these fish could survive the winters out there? I am sure they could find food since they are bottom feeders.