Hi, I'm not 100% sure that they are anchors but they fit that discription. They are thread like appendages that start out small and whisker like but grow rapidly. The two that have been effected the worse are my zebra eel and a tomatoe clown. I have a snowflake moray and a niger trigger that have not shown any signs. The zebra will let me pull the worms off but the formalin bath seems to be more thorough.