Sorry to hear about your anemone. A couple things I would have done differently. It looked pretty good when you first got it. My guess is, it wasn't given what it needed. I would have put it at the bottom of the tank, they like the area at the base of a rock, in the sand. They like to bury the foot in the sand. Also, haddoni don't like any where near that much flow. That much flow will never work, especially with a new one. I would have found a low flow area, enough to take away any poop, but hardly enough to lift the edge of the disk under normal flow. I also would not feed a new one for the first few days while it's acclimating. I used to, I know it's hard to resist, but I've gone through enough to see not feeding works better, generally, there will always be exceptions. Not feeding a healthy one will always be ok. Feeding a sick one will not. Anemone's can live a long time, months, with no food. I've done it. Feeding it when not acclimated, and up to speed, it may take food in, but if it doesn't get rid of it, it will rot inside. There's no solid rules with these things, each one is an individual and care may vary depending on health. Again, sorry about your anemone, it looked like a real beauty.