well I'v been doing some research on them and I know they only eat starfish IF(this is only an idea) I did go for them should I buy a pair or singlenot something for a beginner. they need to be fed starfish and frequently, feeding them can get expensive and most people dont realize that till after they get them. i know some people buy chocolate chip stars and either throw them in or freeze them and crack off peices when needed, others use asterinas and others. but they dont harm corals if thats what your wondering.
Nice! good thinking. I like them 2 but they sound like a lot of work. They are defiantly cool to look at.feeding isn't costly IMO. what i did was had 3-4 stars in my sump and would cut an arm when they needed to be fed. the arms regenerate, so you always have food for them. i would do a pair. just be sure to use a different starfish each week so they have time to heal and don't die on you.