bassett wrote:

Nope goldfish are coldwater, I can remember years ago, when i was a kid, in
the UK, many,many years ago . My old man had a fish pond, and many a
winter the pond was frozen , and the fish where trapped in the ice, My old
man would crack the ice with a hammer, and the fish would get out and go
deeper in the water.
I,m in Oz now, and also have friends with goldfish, they also don't bother
with heaters.

They live in coldwater, but hardly thrive. A dog could be kept in a cage, but it
wouldn't be classed as a cage animal.