Any pics of the foot? Or close shots of the tentacles?
Did you collect it or purchase it? I just saw a group of anemones that came to my LFS that look a lot like yours. They had bright yellow feet/columns and appeared to me to be Heteractis malu.
It's not the "rock anemone" E. crucifer, or maxi mini. Can't be positive what it is though? Maybe H. malu. Maybe something else. There are quite a few species of small, flat, anemones similar to that.
It looks like a St. Thomas Yuma or ricordia.