I have a 3788 gallon pond which I started up on July 4th of last year. I only have 6 fish in the pond so far. I have 2 fantail goldfish and 4 koi. I was really worried about keeping the fish out in the pond over the winter, but so far they seem to be doing fine. This year we have had a mild winter which is not normal but I'm loving it! We still have a couple months to go so who knows what will happen.