i wish mine looked like that. mine is having a tough time putting his tenicles out 100% he gets them about half way and now he has them all pulled in except a few! I had the water tested by my lfs and they said they haven't seen water soo good... so i have no idea whats goen on!
when they start to inflate like that it means that they are unhappy where they are at and are trying to move themselves. yes they can move, very slowly though.