I removed my 6 line with a fish trap. They are very clever. It took several days and every other fish in the tank went in before he did. My 6 line was not only a bully but also loved to steal food from my acans. So I put an acan frag in the trap and fed it and then hid accross the room under a blanket with the string in hand. By this point I think he knew I hated him and was suspicious every time I was near the tank so I had to hide. Good luck. 6 lines and damsels will never set fin in any of my tanks ever again