A mane of tentacles illuminated by sun looks very beautiful swinging in time with the waves.
I suppose there are at least three of actinia here, and the fourth is a little back at the left. They like to have a lot of neighbours.
As soon as freely hanging tentacles feel currents of water issued by a possible prey, they stretch in that direction in the hope of seizing and craming it into it's mouth, that is situated in the middle of a bunch.
This action might be seen at the right.