The amount of fish you get might differ from the amount you end up with. I would start with at least 10, have lots of hidey holes and do FREQUENT water changes and get a filter rated to double or more of the 37g capacity. When the fish start to grow and stake out who's who, you might find some either die, or are just ostracized. I have 10 FULL grown (4-7") Mbuna and two 3" ones in a 65. It's perfect for me and my setup. I have a 37g tank and cannot imagine 10 full grown fellas in there, but for juvies, thats a good start. G L