I'm thinking the aggression might have been worse if they were closer in size so the larger Dempsey would have seen the other one as more of a threat. They're definitely aggressive.It is great to see him shake and shimmy at the other Jack I had in there, but then he got aggressive and I had to separate them before he killed the other one. Funny thing is that they are the same age and raised together, but the other male is half his size. Maybe the other one will catch up now that they are separated.
Shortly after I rescued mine, one of the males ripped the lip off another while fighting/liplockling. I remember thinking "No wonder the guy got rid of these things." lol
Don't do it!!!