Well, I have seen aggression between my male and female. I have them in a 4x2x3 (lxwxh). But now with even your response, though you agree with Mark, you offer yet a different opinion. He says no more than 1.1. I see aggression (not extreme though) between 1.1. You say a trio is fine but still kick ass. I've heard this before, that even in a 10x8x5 enclosure still shouldn't have more than a trio. I've heard though of success in a 6x6x5 with 1.5. It seems the only constant is aggression, but the point that makes difference between manageable aggression and killing aggression is cage size and hiding/basking spot availability. What size enclosures are you guys working with?