My childhood goldfish passed away last week. 
I can't quite recall how many years it lived but it was probably getting on for 20 years!
Very sorry indeed to learn of this,
@Matt; I remember you mentioning him at the beginning and I was wondering a while back if he was still going strong. Sincere condolences.
If you want to start the transition to tropical fish early there are many fish which could go with the goldfish in a cool tank and then be transitioned to tropical... quite a bit of research required if you want to do this but I'm happy to help if you want... again just let me know!! 
A good rule of thumb,
@Garvie92, though, is that if a fish fits in a fish's mouth at all, then it will probably at least attempt to eat/snack on it, and with goldfish being large
and having voracious appetites, you need to be particularly careful.
