I have chalices, montis, tabling acros, mushrooms, favias, cyphastrea, duncans, Goni, anacropora, and euphylia on the back/overflows of my 400g tank. I got the tank used for a steal but it has the 90’s blue acrylic back and overflows. I glued rock to the back when I set it up and have glued additional corals and frag holders to the back and sides over the last year. Corals are a great way to hide that awful blue acrylic!