JoeJoe,
I have had a green BTA for a couple of weeks now, and mine did the same thing for the first week. I have posted on many boards asking what its deal is, as well as getting my trusted LFS guy (not the same LFS guy that I bought the BTA from) to take a look of before and after pics of it, test my water conditions and see that my lighting is good enough. Once all that was established and found to be adequate, the only other assumption I was given is that the BTA is acclimating itself to my water, which could take up to a week or so-maybe more. My BTA moved all over the tank becuse it was not happy for the first week. Make sure you wrap your filter and powerhead intakes with a foam guard (can be purchased at LFS for about 5 bucks). Cut it down and just slip it over the intakes to avoid the anenome from getting sucked up and destroyed. Keep your water parameters good, and give it enough lighting and it should be fine. Mine is doing great now. It shrivels up like that only about every other day, and when I turn off the lights, it opens back up (I guess I got a BTA that doesn't like too much light)
You'll figure out its behavior and get accustomed to what it wants. Having a clown helps the BTA's stress level a great deal.
Good Luck!