Originally Posted by ChoclateBetta
Gold fish are cold water not tropical too so after cycling you would have to get rid of them and adjust temp to.
Goldfish are actually neither. They originally come from temperate waters. This means that throughout the year they experience temperatures as high as 80F and as low as 40F. Fishbase.org lists the maximum temperature for goldfish as 105F. This is not a healthy level to keep them at permanently, but they can survive up to that level. The myth that goldfish are "coldwater" fish came from the fact that it is slightly easier to keep them at temperatures in the low 70's. They need less oxygen and less food (which of course means less poop). In fact the fancy goldfish shouldn't be kept at temperatures below 70F as their deformed digestive tract has trouble functioning much below that. It's really only the single-tail goldfish that can survive at true coldwater temps.
That being said, kfryman has a good point. Goldfish can be voracious destroyers of plants. Best not to keep them in a NPT. It would become a natural planted salad bar.