Yea Dr. Ron said they were impossible to keep to. Somethig about only feeding on the larvae of Fireworms
Anyway I have had a pair of Feather stars in my tank for a year and a half and no problems. They seem pretty healthy to me. They are really neat. They have a small set of legs that surround thier mouth (and they get around pretty quick to) and then what looks like normal legs, but are actually the feathers they use for gathering food. They stay balled up during the day but in the twilight and night they will climb to the highest point or the point that stick out the farthest and spread thier feathers. Really neat to see.
I feed my tank a custom blender mush so thier is plenty of the right sized particles to keep them happy and healthy.