I live in Ohio and leave the gold fish in the ponds (3) over the
winter... use a de-icer when the temperture drops to freezing. It is a
floating stock pond heater, can be purchased in a farm supply store.
Some of the fish have survived sence 1994.The heater is located in the
lower pond with a pump running to circulate the water and keeps all
three ponds from freezing over.
The ponds are 350 to 450 gallons and from 24" to 36" deep.
Regards the water lilies it may be worth taking them out for a earlier
start. I leave them in the bottom of the ponds...just lazy I guess!!!!
Waiting for Spring!!!
Richard