Help! This is my first winter with a pond. The Koi and gold fish I bought last spring have grown a lot, in fact they're HUGE. I'm in North Carolina, where it got down to 10 degrees 2 nights ago. The following day all my fish were on their sides at the bottom. I knew they'd go to the bottom and do nothing but I was shocked to see them on their sides. Is this normal? The pond is 1,000 gallons and about 3 1/2 feet deep at most. I'm seriously thinking of putting a heater ... not de-icer in it simply because I cannot take watching them like that. Oh, I guess I should mention all but 1 are upright again and seem fine. The last one is much better than he/she was but still not normal.