Looks like a rock anemone, but I'm not an expert. If it is they are not bad. This is the description that this site provides. "The Rock Anemone is a small flower-like Anemone. The disk is green, tan, or brown with numerous short tentacles around the outer edge. The tentacles of this Anemone are usually ringed. The Rock Anemone will usually have a pink mouth and the base is often pink or orange. As the name suggests, this anemone will put its foot into a rock crevice and stay there. These Anemones are very hardy and should be provided strong lighting and water flow. Anemones will not tolerate poor water quality." I hope it was ok to post the description