I'd recommend a 3 ft. (30 long or more) tank for any centropyge angels... just my opinion.
If you're going to get one anyway, I'd suggest one of the smaller species of clownfish (ocellaris, percula, perideraion, sandaracinos, etc.). You might have some luck with some of the more peaceful dottybacks instead, or maybe even something like a royal gramma or firefish. I'd suggest adding the more aggressive fish last- in many cases, it will be the angel.
You will need a bigger tank.
-Matt
p.s. Got any recent water parameters?