The african red seastar is called Protoreaster lincki. It is not reef safe, and can and will eat snails, scallops, clams, various types of corals and anemones.
Feed it anything meaty, including shrimp pellets, shrimp, krill, squid, silversides, etc. Algae wafers might be worth a try now and then too. Try a couple of times a week, but pay very close attention to your water chemistry. How big is your tank, and how old is it? You will probably have to make modification as you learn how your water chemisty changes and according to the behavior of the star.
All echinoderms are very sensitive to changes in water chemistry, especially pH, alk and specific gravity. Though these guys are relatively tough, they will do best at higher specific gravity in the 1.025-1.026. Since you have a FO, you may not wish to have it that high, but it should definitely be above the typical 1.019-1.020 range.
Acclimation should be very slow, and if it is too rushed, you may start to see slimy spots or the general appearance that it is melting. THis is and indication of acclimation shock, and can typically not be reversed...though keeping the animal in a consistant environment may help. This stress can show up within a month after introduction. Hopefully you will see no sign of this.
Good luck with the star!