Like what bro andtsg has said, anemone must be allowed to go into the tank and choose a spot first. However, as long as the anemone feels that the environment of it's spot is not good it will move. I have a friend who has 2 LTA in his tank for a whole year le. His is a 4 footer, with aquamedic equipments running very efficiently. His LTAs are damn big and nice but it came at the expense of corals as the stings of the LTAs killed some corals. So do consider what you want in your tank carefully.