At what temperature is it to ?cold? for a Goldfish?

[Master Zero]

Yes it is at 2 feet deep past the sand. I was right when I said 300 gallons. This is the result after using that formula and my new readings, (4'wide x 5'long x 2'deep) x 7.5 = 300 gallons. It is made out of hard plastic (that is what it looks like and feels like to me). Seeing that the pond is not over 4 feet deep then it will freeze solid right? Removing them is not a problem for me I have done it before; I just need to know when. Can someone tell me the “red zone (the point before the water will freeze)?”

Thank you.

 

[Matak]

If you are really concerned, make a veneer of thin plywood to the shape of the pond (if possible) and glue some 2" styrofoam SM to the bottom. Spread straw about 6" thick around the outside edge. Be sure to cut a 3" hole in it for aeration and keep this hole clear of ice. A heater in the hole would work.