I keep goldfish and a variety of other fish in other tanks. Half of the goldfish died last year. They are cold water fish and could not take the 20* drops. Few fish could, cold water or topical.
I'm looking for a way to alter the 40* water without breaking my back or killing my fish. I am very attached to mine and I know how bad pet stores are. If I give my fish away to start over, they will die there.