I bought 25 I think as my first and only colony. Would love to get a massive colony in the future.
They are agro towards each other, and I think I had 4 very dominant distinctive males in the tank that didn't normally venture into another males territory. You definitely need a LOT of hiding spots with these guys. Breeding them is dead easy too. just get a colony and let them go nuts.
best not to buy tiny ones too, I bought all of mine at like 3-4cm and they grow relatively fast. that is the smallest size i would buy them at, but having said that you probably don't want to add large males into another colony either.