Anemone maybe dying

I have a very pretty BTA, it had been very happy and healthy. But about a week ago it started to roam the tank, always ending back where it started. Then yesterday it deflated completely, I also had a bacteria out break overnight... So I don't two 20% water changes yesterday and my nem bounced back.... All night it was very happy and as the light started to ramo up it was all good. But about 30 min ago it completely deflated now it's very small... The mouth will open and close tight. I plan on leaving it alone, but I just want to know if there is something I can do?

 

Well I guess it had to poop? I caught my clown fish cleaning out some black stringy stuff off of the disk and now it's looking much better? The clown even ate some of the stuff?