I have in my sump what appear to be and have been described as "micro feather dusters". In the sump they were fine but they since spread to my main tank. I remenber reading that there was a fish, crab, or shrimp that eats them. I searched but could not find the info. I beleive it was corsis or a six line wrasse.
I don't want to eliminate them just control the spread they are now on 3 rocks in my tank. They were cool untill they spread.
Any info would help. Does anyone have the real name?