I always buy 3 dempseys cause you cant tell if they are male of female yet. Eventually and hopefully, two of them will pair off, then i bring the third back to the lfs. Even buying 3, there is a 25% chance they are all,the same sex. At leaset you cut your odds in half. You could even buy 4 at that size, 3$ each is reasonable. Once you get a pair again bring the other ones back. Your fish are very small and they dont grow so fast that you are gonna get overwhelmed with an overstock tank.