Here is a video taken during feeding time. As other fish come into his territory, he drives them away. But notice the blue marble moves around as she pleases and he doesn't bother her at all. It's this cute little blue marble who I believe John McFish is trying to impress.
A male angelfish must show to the female that he is strong and capable of defending their eggs and young. There will be many who will try to eat both the eggs and the young and in order for them to survive, they must have protective parents.
But so far the female doesn't appear to be interested.