hitch hikers

hey guys i have a few questions on flatworms but first let me add some background information, i currently have a nano aquarium set up for a G. chiragra mantis shrimp and i has some other cuc in there as well but no corals or fish just a marine planted tank if you will dominated by macro algae...

Are these any specific Brittle Star? All of these were in one small colony of WWC Cherry Tree monti. The colony had faded over the last few months and parts where dying off. I could see their legs sticking out of the dead parts but had no idea there was this many. They agitated the Monti and it...