I noticed Herman's head does a quick little bob or jerk once in a while when he's walking. I am starting to add more cal and D3 I had only been putting it on his food a couple times a week. Maybe hes lacking something? I also have a cuttle bone in his home for him to chew on. I have been giving him a little squach and zucinni latley two, plus his spring mix . As soon as the christmass tree bins become available I will get him one and move him out of the 55 gal tank. Thanks for any advice.