Regretfully, I'm very familiar with aiptasia, and it doesn't look like any aiptasia I've ever seen. It looks more like a cup coral of some type. If it's an aiptasia in a light source it should be light to dark tan in color, from zooxanthellae algae in there body. There only clear when they grow in areas void of light (caves or under rock work) in this case they feed on nutrients in the water. And while I've seen a few lay flat against the rock work it's not common, they normally extend there bodies out to get light or feed. And when disturbed pull back into the rock leaving only a soft mass or if there far enough back in the rock work, nothing.