A club for owners of Parrot Cichlids

We had a couple parrotfish which after two times of spawning didn't fertilize the eggs. So my brother and I came to conclusion that this male fish can not
fertilize the eggs, so, we changed it with another fish I really don't
know the name. Literally can be translated into sth like: Monkey
proboscis or snout monkey (white one)! I know you can guess it through the picture:

Anyway, I separated them for the few first days so that male fish gets
used to the new environment. After I put them together, in spite of male
fish's bigger size, didn't hurt the female parrot. but the day after he
had hurt the point between her nose hole.

So separated them again and now I see that they both peck at each other
on the separative glasses!
When do you suggest me to put them back together or what's the point for
this pecking?

Thanks a lot.