the rockscape is basically 3 pcs, with the main sea mountain and the base as the big ones. chose very porous rocks wand allows a lot of caves / crevices for hiding, thanks to Victor. Used Caribsea live sand, very minimal only averaging about less than 1 cm thickness. I set the rockscape on the base of the tank and epoxied with coraline-colored epox. the glued rock is hollow under, so gobies or whoever wants to can swim and hide easily.