here are my 3 clown 2 picasso 1 platinum in one nem.they never fight.jut thought i would post this to show you can have more then 2 in a tank.the platunum is the female and the other 2 are the males.sometimes i see the two males an the same nem.i also have around a dozen bta in my tank so i dont know if that helps with the clown getting along.
but all three get along great.