I also had success keeping 2 different pairs together 2 different times with other fish BUT....my tanks were way bigger than a 75. I think that is what made the difference in my case. Had my pairs been in a 75, they probably would have killed each other.
Ive also noticed, in most species, not all, that if there are a m & f and the f is bigger, she will tend to kill the smaller male. Natures way of thinning out the less dominant/ weaker males to spawn with and carry on the species with the strongest id imagine.
Yeah, that is what I'm scared of. I don't care if they spawn or not, I'd much rather have 1 real nice male specimen than have to figure out what to do with a bunch of babys. They are close in size, the Female might have the Male by a couple millimeters. I'll take some shots when I get home to see what you guys think.
I'd rather not divide my tank. Probably sell the female if anything. But if they can co-exist and form a pair, that would be nice too...just don't want my male dying.