My pond is at 52.1F right now, which is very close to the limit where Koi should be fed. Any colder and the food lays in their digestive tract and rots. But today they think summer is returning, judging by their reaction to me greeting them a couple of minutes ago. I quit feeding them a couple of weeks ago when the water temp descended into the mid forties. Gonna give them a little light lunch today. When the temp goes down, they generally descend to the bottom, about 5′, and line up like cordwood, ignoring me.