When the day time water temps go down to about 50 F I switch to a spring/fall food, then when they go down to about 40 F I stop feeding. If the temps I go by are wrong then, hopefully, someone will set me straight.

I make sure all leaves are scooped out of the pond in the fall. I have a small 160 gal pond. I don't usually have any sludge. I use MicrobLift; I don't know if that contributes to lack of sludge or not. I do believe that it is important to go into the winter with as clean a pond as possible.

Anne

I start feeding wheatgerm food at 55� and stop feeding at 50�. And get the pond as clean as possible in the fall. It is healthier for the fish to overwinter in a clean pond.

I normally start feeding a spring and fall diet when the water temp gets to 55 F and I stop feeding altogether at 46 F. At 40 F they hybernate.

I clean out all the fallen leaves, seasonal plants and as much algae as possible in the fall. Gases are given off by rotting debri and polute the water, but dont worry if its not perfect, Gases will escape as long as the pond doesnt completely freeze over.

Here is a link that might be useful: Feeding Koi Fish

Koi do not hibernate. When an animal hibernates, they are unaware of their surroundings. It takes a lot to wake an animal from a hibernated state. Hibernating bears are often pulled from their dens to do studies on them, and they don't even wake up. They are dead asleep. That is true hibernation.

Koi are cold blooded creatures and in the winter, they slow way down to conserve their energy (a degree of stasis). They are sluggish, but very much aware of what's going on around them and can easily take off and swim normally if they feel threatened.