can aiptasia grow on acropora?

[KJAG]

thats a coral polyp. If it were anytign else, there would be receeding flesh at the top and I dont see that in the 2nd photo.

He just said there was

 

[elderdaffodil]

It looks like it is the axial corallite polyp but it's also hard to tell for sure. Does it retract at the same time the others seems to retract given different stimuli? Does it ever stay out when the other polyps are retracted?