This beautiful anemone was about 12 inches across. Comparing the centers and unusual tentacles this type of anemone muct be closely related to Zebra Anemones. See Zebra Anemone with Shrimp and Anemonefish in Zebra Anemone. Note the tiny fish here which was about one inch long.
The maximum size for this square image is 8 x 8. Link to Colorful Anemone for the oblong image of the same subject.