Has anyone tried using rigid insulation floating on the pond to keep the
water temp up a few degrees. I normally run a small pump to keep a hole
open
for gas exchange but last winter it was so cold here in southern Ontario
that it froze over anyway. My pond is 1800 gallons and 3 foot deep with 50
to 60 fish of all sizes up too 18 inch's. Any suggestions would be greatly
appreciated.

Regards
Norm