I have a clown in my wife's classroom tank. He was my first fish in the current cycle of piscomania, starting in a 10, moving to a 20, then to a 55, and now back to a 33. Cute as a bug's ear, but stays out of sight almost all the time. Didn't have any problems sharing his cave in the 20 with cories.
Must have driftwood. It's a big part of their diet.