Don't go with a single redbelly. They all have different personalities but i'd say it's a safe bet that it'll end up having the personality of a couch potato. It'll be shy and skittish and if it ever breaks out of that mold, it'll just hover in one spot, belly on the substrate.
You'll be disappointed. Your fish will be unhappy. You'll end up having to give it to someone else that'll be disappointed...or someone else will introduce it to their already established tank without doing the research and it'll get killed and everyone involved will be disappointed.