Perhaps I was doing something wrong, but I've failed three times trying to keep a group of juvinile Pseudotropheus saulosi in a 30 gallon long tank. Every time, I ended up with only a single male. Now granted, I didn't buy them sexed and try 1 male and 3 to 4 females specifically, but I did start with a larger group of juviniles than 5 all three times. Just my $.02 worth