The Aimara i think is a beast, he's a very nice looking fella.
When i introduced mine i actually thought my Temensis was going to eat him, my Ripsaws would come and sit on top of him - i even saw my 12" Azul joining in on the 20" Aimara.
That was interesting.
He settled a few days and attacked everyone in the tank and then calmed down once he made his mark - now they all live well together but i do see him show them who's boss now and again just to remind them.
I never had CK down as aggressive fish really, with fish i find it's not always who has the bigger teeth, who's the biggest or basically the one with the biggest artillery who's the aggressor.
It's a case of "he who dares, wins"