Starfish don't tend to require much feeding. I have several serpent, and brittle stars that I feed a piece of krill to approx twice a week. I only had a chocolate chip star for about three days. I had to take him back becuase in that short time period he had eaten several small sponges and other growths off my aquaculutre live rock. I would keep a close eye on it, if you like anything that is growing on your live rock. They are serious scavengers.
Generally stars don't require much extra feeding. They are pretty good scavengers and eat what ever left over food they can find. I usually feed mine a small piece of cocktail shrimp once a week or so as a little snack.