New Goldfish? Help?!?

So a few days ago, i won a goldfish at a fair and i had it in a bowl (TEMPORARILY) and now i put him in a one gallon tank, with under gravel filtration and an air pump and air stone. I would say he has a pretty damn good set up. Im just wondering if everything is good, if he grows i will eventually upgrade him of course. Also, Im currently feeding him baby shrimp is that okay? Or more variety?