Yea sure, 5 small goldfish will live in a 100L tank when small, but if you just wait until they outgrow the tank, they will get stunted. People put large goldfish into ponds, thats why you dont see them much. also, in a tank they wouldnt grow that big, because of the whole stunting issue.....
YES, you do. well, at least you should, but some people know better :roll:
You seem to not realy know exactly what you are talking about here, so best to not dig yourself into a hole