What size is your tank?
Is it cycled with a beneficial bacteria colony to keep water parameters stable?
One or more of the males (if there are several) will be unhappy because their hierarchy has been disturbed. Competition for a mate.
The original male will probably never be happy. If you change the tank decor around, add some very tall plants to create smaller safety zones it could help.
Very likely even getting rid of one male, a new one will be the angry one, always about mating and protecting fry.
When they are raised together often there is a better chance of getting along. Adding in new fish creates havoc as all the usual situations are changed.
Males looking to get the best female.
Fish will fight and can tear the other fish apart leading to death because of injury and or stress.
I have lost Angelfish, lost his mate to a new male and he literally tried to get her back other male was stronger and she liked him better, and he eventually just died in a corner. Like of a broken spirit /heart.
Others have just fought over a female until they were both looking like went through a shredder.
Angels are not angels! In our tanks (mine was a 72G) there really isn't enough room for the fish to have proper territories like they may have in nature. So there is unrest, and fighting.