Your anemone looks very stressed but not deteriorating yet.
I suggest you post all water paramiters, include temp, ph and calcium and alkalinity.
How did you acclimate the anemone?
I would further suggest that you get it away from the intake to your filter, or raise the intake so it is not so close to the bottom.
My first guess is that it is suffering from acclimation shock, it looks tight, stressed but not dieing.
Thomas