Waited about 1 month to add inverts and about 2 months to add corals. I know I broke the "recommended rule" of six months for any coral additions but I've always been somewhat of a rebel. I started off with mushrooms/polyps and now (6 months later) have hammer, blastumussa, brains, 2 small clams, flower pot, 3 diferrent bubble corals, 1 acropora, etc.... So far the only thing that's been unsuccesful has been a brain which was damaged during shipping(couldn't save it) and 2 fish which were killed by a bristle starfish.