Yes get rid of it , small are beneficial , big ones like that will strart to attack corals,clams and such pulled one out of my tank 10 inches long. There was a thread on here about a year or two ago, I think he had like a 400 gal and he started havind big corals eaten, he had a PVC frame for rock work and the worm had lived in there for years,he had to dismatel everything to get him out. I think he was actually 4 ft long. There was pictures. IT WAS NASTY> It was soo big he had to throw it away in the garbage- you certainly could not flush it!!! :scared: