I live in Michigan and have small pond about 5 x 6 maybe 300 gal .......and
is about 15 to 16 inch deep...I have 6 goldfish about 5 to 6 inch's and I am
concerned that pond may not be deep enough for them to survive......I do not
have place for them inside.......I am looking for a low cost option.....any
advise would be appreciated...