Malawi MaD
Fish Herder
3 to 6 ideally. Not to many, even though this species is less aggressive and can be in smaller tanks the males will still have a rant with one another if there is too many. I saw in your pics what looked to have the potential to be a couple of males. Venting them is the only true possible way of knowing what sex they. They will start to show some colour soon enough mate, when you getting the others.