Will I need a air stone or bubbler for winter? Our pond is 4 ft deep by 8 ft by 14 ft. I use a round floating deicer and have 3 koi and 3 dozen goldfish that are 4 yrs old.

Koi may still need some aeration. The bubbler such as the AquaForce pump work until the temp reaches 25 degrees and then the De-Icer will kick in. Cold water holds more oxygen than warm water. It all depends on your climate whether you leave you pond running or you want to shut it down and use a bubbler in combination with the De-Icer.