I have 8 gold fish and 5 koi (new this year). About this time I pull out the fish to winter them in my basement. This year I have pulled the goldfish and all are doing fine. The koi have all hidden behind rocks so I can't see them to get them out. I have heard that there is some sort of heating device that I can put into the water that I am hoping will help them out. I just need to get them visible so I can net them. Any ideas? I really don't want to lose them, but there fate is doomed if they stay where they are.