I think it's a great idea.............
As long as you don't plan on keeping any fish in the tank with him other than goldfish.
As long as you plan on having a tank size suitable enough for him. 20+ gal for just 1 fish. Absolutely no mini-tanks or bowls.
As long as you don't mind have the same fish for a possible 15 years.
As long as you do that I think it's a great idea. Goldfish have a reputation as a readily disposable beginner fish. I found out quickly that goldfish actually have very special care requirements compared to tropicals. Not that they are more difficult to take care of but they are different. Cold water tanks, limited vegetation, limited compatability with other fish(ie. almost none). But I also find Goldfish very rewarding in that they have more personality than most fish I've seen and I like the idea of 'big' fish as opposed to 'many' fish. 1 or 2 full size fancies in a tank would seem to be more of an attention getter than a few barbs and a school of neons.
If you do get a 'goldie' then I think you'll enjoy it very much, just be sure it is what you want first.
