I think it is a Stichodactyla gigantea.
Beautiful anemone Heinz!!
Hate to tell you this hma but thats a bleached out seabae anemone i found out. It is bleached out deliberately by keeping it in the dark. I also found out that they die after a few months to a year also.Agree 100% Doni. That is a Condylactis gigantea.
Here a picture of my Condy…