Brittle or Serpent Star?

I want to add either a serpent or a brittle star to my 90 gal tank, but there seems to be conflicting opinions on which one is less likely to eat fish. While researching, I would frequently read information that said serpent stars will eat fish more often. Then I would find a website that said brittle stars are the ones to avoid. One LFS in my area said that serpent stars are the way to go while the other said both brittle and serpent wouldn't be a problem. Now I'm just confused. I would like to hear what you guys have to say about them. Anyone with experience please chime in.