what are these white root looking things?

[The Guy]

I have these white thin root looking things sticking out from behind some corals, just wondering if they are a problem at all. Also have what I think is sponge on some of my LR and seems to be overgrowing some zoes. You can see the sponge at about 11 o'clock on the rock behind the trumpet coral along with these thin root looking things. As well, are these tiny 6 legged star fish a problem All comments welcomed.


Thanks for looking.