The resion I said to use live rock was cus the worm will hide in it after it has eaten. Then u pull the rock out and let it dry out. Criter dead and one down. Make sure sure u leave the rock far enough from water there is no possible way it could get back in tank. The polyclad flatworm can move on dry surfaces. I fought those thing for a year. The only option for me was dry out and start over. Hope u don't have them they suck testies.
