umm..
I don't have a common anemone. Instead I have a Hatian Pink Tip Anemone. In my experience, as long as the anemone is attached, whether it is withdrawn, its a good thing. My anemone has been withdrawn completely before and its still doing fine.
However, i had 2 anemones at one time... the other one had passed, and the behavior i saw from him was that he would be detached very often and withdrawn most of the time...ultimately i found it dead one morning.
Again, i don't have the same anemone but i've read that a moving anemone is an unhappy one. The anemone i have now that is doing well has basically been in the same spot on the same rock since i put him in.
I'd do a google search and read up on your anemone...perhaps our feeding to often (which was my problem early), maybe its a light dependent species or needs a certain wavelength of light or perhaps thats the behavior . Unless it is common for you anemone to move, a moving anemone is an unhappy one
