montipora question

I have two montipora, I've is a red montipora capricornis and the other is a purple encrusting montipora. They are both on the same rock and where they have grown together it appears that the purple montipora is waging a war and is winning. I was hoping they would grow together and make a cool pattern but it appears not.

So, do I need to move the red montipora or is this normal when two interact?