There are 10 of them in a same tanks now, at least 5 males. The eleventh is already in his own net breeder thingy in the same aquarium.
The magic is that they are only babies, even when they look that adult already. And they have been living together since the day they were born. The males need to be separated when they will start to show aggression, and that day might be soon. But now they are getting along fine
I have had two adult males in a same tank two times. Both pairs were raised together and the tank was huge with lots of plants and hiding places. There were also lots of girls. It worked fine if I just didn't change the decoration and "territory marks", no teared fins.
But it needs really large tanks, boys that have always lived together and clear territories. And some expertise from the owner. If you buy adult or young males, it won't work. You really need to raise them yourself, and even then it might not work. You need the kindest males and never remove other one for even minutes. You really need to know what you are doing and why. So I don't recommend it to anyone.