I started with 4 about 8 months ago. They were originally all females. It was not long before 1 turned to male. Interestingly enough counter to comments above, it was the male that died. Some sort of illness however, I am certain. It did without question keep at the next in line female pretty hard. No damage or anything, but for sure was more aggressive to her. When he died, that same female transformed within a matter of weeks. It's been about 3 months or so now since then, and it's like it is stuck a bit in it's transformation somewhere in the middle. But the 3 are perfectly happy with each other. The other 2 are almost exactly the same size.