It's normal for seabe anemones to move around the tank. The first location that it chose most likely didn't fit all its needs, thus why it had to move. Anemones (unfortunatly) do not have a central brain and cannot adapt to different locations that it wouldn't get in the wild. The location that the sebae is put into must match exactly what it would receive in the wild. I would leave it and let it roam around the tank at its own pace, as long as there isn't any open powerheads near by that the anemone could get stuck in.
He was originallyattached to a rock which i have found out is a no-no and he has been placed in sand since three days ago.
Sebae's do not need to be placed in the sand. Sebae anemones are actually more rock boring anemones.
Also, may I ask what your tank conditions are? Such as lighting, filtration, how old the tank is, what color the sebae is, what fish you have, what filtration you have, what tank size, all water parimeters (pH, nitrite, nitrate, ammonia, calcium, alkalinity, temperature, salinity, etc.) The more information you provide the more accurate reply you'll receive.
Take Care,
Graham
