Question
Hi. I have 6 Koi, 2 goldfish and 2 catfish in my pond. I'm going to install a pond
heater this winter. What temperature do you recomend I set it at? Also, should I
keep it warm enough for the Koi to be active all winter or just enough to prevent
danger to Koi? I live in South Central Pennsylvania. My pond is 2 and a half feet
deep in the middle and the pond is 2500 gallons.

Answer
Hi Dale,
Quite a lot of koi keepers here in the UK heat there pond over winter usually at aprox 18C to 20C degrees as long as the temperature of the water is over 15C the koi will continue to eat.
I do not heat my pond and I have koi that have been swimming in my pond for thirty years, you can see my koi and pond on my website at http://koi-z-are-us.20m.com
George.