How long has the tank you are intending to put the anemone in been established? They need stable, high quality water to do well. Ideally with good flow (turbulent) and lighting. Even in tanks with apparently good water quality anemones put their toes up or into something mechanical. Don't worry about anemones finding there spot - they will keep on shifting, floating, walking over corals, until they find a good spot for themselves. Usually this is the furthermost spot from where we picked.