I have a large blue dot Tamarin that eats them as well as those mini stars. I still have hundreds of them because thy learned to be nocturnal when all my wrasses are sleeping... LOL. It reef safe in that it doesn't touch any coral, but hermits and shrimps are on the menu.
Give it time, the starfish population will go up and drop down to almost nothing in a year. Had it happen to my micro brittlestars, the tiny starfish, my little limpets, etx. Everything does it except bristleworms. LOL.
I have a pair they don't make a big mess in my tank because they made one big den under 1 of my main rock piles they will make different new entrances to pop in and out at different spots of that rock pile but they only leave den when I feed for few secounds