i have never heard anything about meaty foods causing an increase in aggression, in any fish species. pacu are omnivores and eat plant and animal matter in the wild. the only thing that increases aggression or prey drive in fish is feeding them live prey, something they have to actually hunt or chase down, with that being said feed ur pacu veggies and sometimes certain meaty foods....stay away from beef heart. fish dont digest mammalian meat well. some members feed lettuce, peas, cucumbers and etc. as far as meaty foods, insects, pieces of fish filets, shrimp, also a good pellet would be great as well....good luck....
