Little white worms..feather dusters??

[dem0n321]

I just recently bought a small piece of fiji live rock that had an empty clam shell on it, when i got home and placed it in the tank i noticed that there were little with strings curled up, then just today i took a closer look and i saw what looked like fans comming out the ends of them, i was wondering if anyone could ID them for me and tell me how big they will become.

Thanks _Tom

 

[Len]

Could be anything from small Sabellid feather duster polycheates to Serpulids (if it has a hard calcium tube). They could also be Ctenophores (comb jellies). This is a small list of the possibilities, and it's really hard to tell for sure without visual aids. But rest well knowing that all filter feeding hitchhikers on the rocks are as safe as you can ask for