I have some ghost mantids and a Whites tree frog (Freddy) in my 18/18/24 exoterra. The ghosts like the screen top and fine twigs to live on and Freddy climbs down to eat on the floor of the exoterra. I dont think he can reach the ghosts. They are small, 1 1/2 inches in length and light weight. Freddy's too big to get at them. They dont carry disease as far as I know and they will not try to attack him.