mid posted

I've kept koi & goldfish in Southern Ontario with temperatures down
below -20C and a foot or more of ice on the pond.

I use a bubbler to keep a hole open - originally I put an airstone on it,
but I kept losing the stone

Hi Derek - I used to lose the airstone sometimes as well (I used silicone to
'glue' it to the airline) - I found the answer this year :~) - pvc cement
and I even tried to knock it off - & it's still on
Gale :~)

A standard 15W
aquarium air-pump can keep a hole open in all but the worst conditions,
for
a lot less money than an electric heater.

Really, the worst part about ponding in Northern climates is not seeing
any
pond life for half the year...
--
derek