Unknown starfish

Anyone know what kind of starfish this is? I assume it hitch hiked in at some point but I just noticed it today, first time I have seen it when the lights are on. It was climbing on the side of a Kenya tree in this photo but soon after moved off on to the rock. It doesn't seem to be hurting anything.

 

What color is it and its size? 5 legs?

 

5 legs mostly white or cream colored. I have a sand sifting star that I have had in the tank for a long time. But this star is much smaller, probably an inch across tip to tip. I have also found 2 more stars last night, very small, much smaller than this one. They are in my over flows.

 

It might be an asterinea starfish. If it is you'll want to remove all of them. They spawn like crazy and can hurt coral. I had them take over my tank. I cured the problem with a Harlequin Shrimp.