As they get bigger, typically the reds start to fade, so I tried raw carrots once, and he wouldn’t touch them, but I was feeding big color pellets at the time, and started chopping them up the size of the pellets, soon he was gobbling those carrot chunks up Just like pellets… at that point I started mine on baby carrot sized pieces, & before you know it he was picking up and chewing whole carrots… we used to get company, come over just to watch “Buddy” eat carrots, as you could hear him chomping on them through the glass and water… at that point in our lives, we had several varieties of birds, and I had a lot of big fish, so we never knew when friends, would bring their grandkids by…
BTW, they are often known as vegetarian piranhas, but they are really omnivorous… mine ate gold fish quite often, but that was curtailed, as he got bigger, by the time they are mid sized, they can empty out a 1/4 of an aquarium trying to catch a few goldfish…
It’s kind of like having a Great Dane, in comparison to a little dog… the Great Dane, doesn’t make a good lap dog, a Pacu doesn’t get, that he’s a 100 times bigger, and they are athletic, so the tanks need covered, and put something heavy on the cover, and be prepared for lots of water being splashed out of the tank at times, so vinyl flooring is a good choice around a Pacu tank