Honeymoon is over

[Yoda1]

These things happen unfortunately.
When you bought the fish, some if not all were immature?
As they mature, the males like to assert themselves and establish a "tank boss". It can't be avoided with Mbuna.

Nice tank.

 

[Mokujin22]

Your tank size, scaping and fish selection looks good to me.

Kenyi are little SOBs. I think that folks who try to breed them recommend a 75 for adults.

Keep the faith... mbuna are pretty rough. If the male keeps taking out other fish, you might have to take him back to the pet store for credit. Good thing about female kenyi is that they're still cool looking fish, even without a male in there.

Good luck.