I have some of these, too. My biggest is a 9" or 10" beautiful male in my 180 at work.
I have not found these fish to be all that aggressive. The don't get bullied too much, but I don't see them owning the tank, either.
I got mine to help by predating on fry that are overrunning several tanks, but I must have bad luck. My comrepssiceps are pretty inept predators...
Cool fish, top/middle swimmers, and they need a big tank. Even a 75 might be a bit cramped for them.
Enjoy!
Jim