Bta Ok?

My BTA found a little spot on my rock, had been there for months and seemed to be doing quite well, all big and growing. 2 days ago, he moved to the bottom corner of my tank (where there is very little flow as it's underneath a powerhead). He's much smaller, but still seems alive as he's shrunk and puffed up once or twice. He's facing the back glass and wedged between a rock and the glass (foot on the rock). Water seems fine and has been for some time (based on my tests and LFS). Is this just normal anemone movement that I haven't had to worry about, or does this sound like he's toast? Nothing has changed recently, so I'm not sure what made him decide to move from where he's been for literally probably 6 months.

 

Anemones are very, very mysterious. No one really knows how those guys think. Mine had been hanging around the same place for about 3 weeks, seemed confortable with the clowns and everything, then went back and hid. Very little light, very little flow. Now, he's in the back of the reef, zero light, low to zero flow and completely isolated.

He's not toast, atleast it doesn't sound like it, just leave him alone and let him do his thing. If the powerhead might cause him harm, move him out of there asap.