There are quite a few more factors to worry about when keeping corals as well as different corals having different needs. Alkalinity, magnesium, calcium, pH, nitrate, phosphate, dissolved organics, tank temperature, proper lighting, feeding, etc. all need to be thought through.
Feather dusters use calcium and carbon to build their protective tubes.
Head to a library and see if they have
Aquarium Corals by Borneman or the
Book of Coral Propagation by Calfo or buy these books if you're serious about keeping corals. These books will pay for themselves by giving you advanced knowledge before you buy coral on whether or not you can really care for it. Also, go SLOWLY, take your time and enjoy it. It is a lot of fun.
Xenia is not a bad idea for a first coral in my opinion.