Is my bta dying?

[Don's tank]

So I currently have eight bubble tip anemones that all started out from one single one. Currently there are seven that look healthy and are acting normal. One has stayed up near the top of the glass for a couple of months and will open a little bit but spends most of the time closed. Does anybody have any ideas or suggestions?

 

[Spare time]

As long as the foot is attaching and the mouth isnt gaping open I wouldnt worry