Either a terebellid polychaete (AKA spagetti worm) or a cirratulid polychaete (AKA hair worm). The picture doesn't show enough detail to be sure. Both are harmless detritivores.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.