ahh.. what kind of stock tank, plastic or metal? where is it located?
If it is metal you will need to get an insulating blanket all around it, even under
it to keep the heat in. pink foam insulation for under will stand up to weight I
think. any kind of foam from upholstery store or fabric store should work with
plastic around that.
if it is plastic rubbermaid type stock tank, it is insulated already and only need
insulation over the top. clear plastic to let light in. bubble wrap better.
even with the heater on the outside temp will dip. but it is better for the immunity
of the fish to stay closer to 50o even if they arent eating.
Ingrid

On Sat, 8 Dec 2007 11:52:30 CST, "Bill Stock" wrote:
Yes, it too cold for them to eat now, that's why I'd like to warm them up. I
was considering some kind of tarp with bungee cords on top of the stock
tank, which would solve my aeration problem, but may not hlp much with
insulation. The heater is fighting a losing battle at the moment, so I'll be
turning it off until I find a better solution.