"CorporalJones" wrote ...
Was it in this NG that I read that with ponds it was no longer required to
clear a hole in the ice to protect wildlife.
Followed that recommendation and ended up with multiple floating frogs and
goldfish.
So much for the experts!!!

That usually only happens if the water quality is nasty (high nitrite
content), oxygen levels low, and lots of rotting detritus on the bottom
leading to gasses of decomposition. A saucepan of boiling water placed on
the ice will thaw a nice round hole allowing the gas exchange with the air.
Never break a hole as the shock wave can kill and injure fish.

--
Regards
Bob Hobden
W.of London. UK