Well my son calls me at work and says he's standing by the pond and all the koi are gone. I don't have to tell you how i felt. So i get home and go take a look. I found them hiding in the cave in the deep end. The water is kinda chilly but the thermometer i bought says 65. I hope nothing was trying to get at them. I'm gonna bring home my digital thermometer from work this weekend to double check the temp.