When I say pair, what it actually is, is the tank is divided into thirds, 3 areas by 3 dominant females that the alpha males visits at will. There are 5 sub individuals left with only hidey holes, there is also a fry or 2 from one of the spawns in small nooks and crannies.
The dominant females defend their territories from each other, and any other females and non alpha males.
The male harasses any male, or any other non territorial females.
I started with a dozen, and in the beginning I expected in the to end up with only a pair, the scenario I have now, is quite unexpected.
The only time I've had a death, is when I put a male and 2 females in a 50 gal.