I have had good luck keeping my 300 Gallon tank overstocked to keep down on aggression. I change about 200 gallons of water 3 times a week and have 3 FX6s filtering. Tank has been running like this for over a year.
I did recently get rid of a very large red belly Pacu to give everyone some more room.
I did recently get rid of a very large red belly Pacu to give everyone some more room.