Are these bristleworm larvae? When fragging 2 leptoseris corals, I've found families of these worms living inside (between coral and frag plug). The corals that were fragged were in good health, but worms living in corals is never really a good thing in this hobby. Just trying to correctly ID so I can choose an efficacious solution for getting rid of them.
Images are from a microscope; worms are about 0.5cm - 1cm in length when they are fully extended
Images are from a microscope; worms are about 0.5cm - 1cm in length when they are fully extended