I had a Haddoni for several years. It was a nice addition, I had a pair of Clarkii clowns hosting in it. I loved it. A couple of tips. They like to bury their foot in the sand, up against some type of structure. Second, if they move...they aren't happy. If they settle in to a location where you don't want them you can move them by changing the flow. I could always get mine to move by putting it in an almost direct flow from a powerhead. They like water movement, but not a direct stream. Finally, they need food. I fed mine large chunks of fish and shrimp from the seafood counter at least twice a week. Whenever I made fish for dinner, I would keep the trimmings to feed my anemone. At its largest my Haddoni was close to 15 inches in diameter. Sadly, mine died when I tore my tank down. They are really cool anemones, and I want to have another some day. (Ideally I want an Haddoni with a pair of Saddleback clowns)