i think the coral beauty will quickly outgrow the 30gallon tank. But that is just my opinion. I think the only angels you could keep in a tank at or below 30g would be the c. argi, c. acanthops, and c. flavicauda. Most others will get too big/ not be able to find enough food to eat. There are plenty of other fish you could get for it, the percs are nice, all kinds of wrasses (pink striped, 6 line) there are tons of basslets (swissguard), gobies, psuedochromis. Lots of stuff to choose from for sure.