Sea stars?

[LBReefer]

I have no idea where these sea stars came from. I haven't added anything to the tank in months. Are they friend or foe?

This one is about 1/3"

And this one is about 1.5"

 

[samnaz]

both asterina stars. some types have been rumored to nip certain corals but I haven't witnessed it, friend IME.