I've always loved the payara, nile perch, Distichodus type large and most of the time predatory fish. The problem is my largest tank is 75 gallons and it is completely stocked to and possibly over the brim! The closest thing I have now are 3 yellow perch which even though I've only had for a few hours are already awesome, which makes me want this type of fish even more since they're so similar . Is there any aggressive, personable and predatory characin type fish that I could fit in a 40 or 50 breeder for life?