Wow, look at this tread just reminded me of my "Chocolate chip star" that WAS reef safe. It never killed any of my reef stuff.. Anyway.. he's in reef heaven now.
all those mentioned above are reef safe, linkia tend to not do so well in captivity. sometimes u get lucky sometimes you don't. Fromia starfish, serpent, linkia, sand sifting, brittle, serpent are all reef safe. The ones you want to stay away from is the chocholate chip star and any that look just like them.
drs. foster and smith website has a listing of stars and it tells you which is reef safe in the decription, if you wanna see what they look like.
btw, sand sifting, brittle, and serpent starfish tend to hide alot, brittle and serpent stars are nocturnal feeders (most stars for the most part are) but you will see the other stars a little more frequently around your tank during the day.
And make sure you have no harlequin shrimp or from the harlequin family in your tank or you will find a dead star in the morning in pieces floating around your tank like i did. Had a bumble bee that i didn't know was a star eater. Store didn;t tell me and only one site had that fact on it. Was pretty pissed the next morning.
My Blue Linka from FT has been in my tank for almost a year without any issues. It moves all over the place and seems real happy. I use to have 2 serpent starfish and a brittle starfish and they really only cpme out during feeding.