This is diane4 using my husbands machine as rarend.
In my experience so far with anemones and what I have read, most anemones will move to a spot in the tank that they feel most comfortable. Mine tend to move downward if they are in a spot that is getting too much current or not enough, or too much light.
You should also be sure that he didn't move there himself and he didn't fall. I say this, because I spend a lot of time watching my reef tank and I have seen them lean to one side, particularly if they are on a rock so their foot isn't flat against the rock and they either turn toward the current or away from it to go through their cycles of inflate/deflate.
I have seen instances where the anemone, I believe fell off the rock he was on or was competing for space on a rock where he got too close to another anemone. So, my point is - most people say, anemones will move to spot they like, don't move them, it stresses them uncessarily. I would agree with that if you have been watching their behavoir and you are sure they chose to go to that spot and not land that way from a fall.
I also think you can tell if they went to the new spot on purpose or not, based on the way and position they are in in the new spot. When my anmeone fell, he was upside down, mouth and tenticles facing the bottom floor of the tank. In that case, I chose to pick him up and place him back and watched from there.
As a suggestion to offer, I would like to share with you what I did with my LTA that I call Snow White. Snow white does not like a lot of current, and not close to light. I have read that they like a sand floor to stand on. However, right now - there is too much rock in the tank and some will be thinned out soon. I read on this forum that some folks have found at a local hardware store, like home depot or lowes, some PVC pipe or fittings appropriate for the size, legnth and shape needed to meet the housing needs for the anemone. Here is what I did with Snow White. I bought a 1.5" wide black rubber fitting that is about 4 inches high. I washed with plain water the black plumbing piece really well. I attached a flat end cap to create a cup like structure. I then, took the unit and half filled it with sand. I then took some of the tank water and filled the pvc cup up with the water so I could get the sand to settle in the cup, before I put it in the tank. I then securely placed the black rubber cup structure in a spot that I think my anemone likes medium current and medium light. Then I placed the anemone into the cup that is half filled with the sand. After about a 1/2 hour of recovering from the stress of the move, she opened up, leaned on the side of the cup I made and relaxed. She has not tried to move, she doesn't seem stressed, she has soft sand at the bottom and she is secure. I think she is very happy with the new housing arrangement.
I have read that some anemones prefer rock while others prefer a sand bed. Long Tenticle and sabaes prefer sand, and I think the BTA's and Condy's like rock or sand.
If your anemone generally stays put in his/her spot, then you most likely have a happy anemone. If they constantly figet and move around, they are not happy. I feel that what I did for my Snow white was observe places in the tank she did not like so I can learn what she did like, and then create a comfy and secure home with a sand bed within the middle of the tank with sufficient current and light. I will still continue to watch her to see if she developes any signs that indicate she is no longer happy there. The structure I made for her when half filled with the sand is long enough to securely hold her and she feels a comfy "nook" and her top part of her body, tenticles and mouth is above the top surface of the cup structure so she can be seen and absorbe light and current as she feels she needs it.
I think most anemones like to set their foot into a nook where they are secure, substrate or rock all around their foot. You can find pieces of rock that you think has a nook about the size of their foot, and you can place them near it - but you can't make them settle there, they have to discover it and like it.
Now, my bubble tip anemone is in a rock nook and he hosts a mated pair of Tomatoe clowns and he does not move from his spot. He deflates and inflates to eliminate and refresh his system, but he hasn't moved.
My Condy is happy in his nook of rock and well, my sabea, I am not sure what he prefers yet. As I understand it...sabeas are difficult to keep alive and/or happy. I don't have sand on the bottom because it makes cleaning the tank easier. That is why I developed the special home for my anemone with sand in it.
Where did you place him and how did you acclimate him to the tank? He might have moved because he was stressed from going from the lfs to his new house. He also might have recently arrived at the lfs and that in itself is stressfull for the critters.