It's a teeny tiny white starfish I found on my glass. I called the LFS I got my coral from and told them I got it as a hitch hicker and should I take it out. He said I could leave it.
Is this true? It won't hurt my tank?
I think you're referring to Asterina starfish. Some say they can do damage to SPS while other say they are harmless scavengers. I've only seen one in my tank...no problems.