[christyf5]

flatworm exit or any flatworm remover will likely not kill your worm. flatworms have a very thin skin and they easily transmit the FWE across their skin and into their systems, killing them. The worm you have is armored and very thick skinned. I had one of these worms in my system about 8 years ago and it was 2 feet long. My method was removal of the rock it lived in and then chiseling the rock apart to get the worm out (broke the rock into 3 pieces, it was annoying but then so was losing fish/corals to the stupid worm). Letting the rock dry out will take forever as if the rock is quite porous there will still be a lot of moisture in it for the worm to survive. I'd say the hydrogen peroxide/water mix method may be your best bet but if the worm is really holed up in there you will have to wait quite awhile to cycle the rock with the decomposing worm in it before you can return it to your tank.