Ok, I have played w/ enough ponds to just be dangerous. I have agreed to clean a pond for a customer. This part doesn't worry me, and I've done this type of work before. The pond has a population of established Koi. Draining the pond down and catching the fish is something I have again done w/ success in the past. My question................. It turned off cold this week and we've had frost the last two AM's...this AM has a low of about 27 F. The water temp is just over 50 and the fish have become active. If I wait till later in the day instead of early this AM to do this project (total time should be around 4 hours), am I risking harming these fish? Thanks in advance for any quick replies.