I honestly think that it's the coolest fish in the world. I have 2 pacu's, 2 oscars, a jack dempsey and 2 plecos, but out of the whole tank I like these fish best. They eat almost as much as the oscars do. They eat anything, from water melon to regular fish food. I've even seen them eat the feeder minnows. So far I've had them for almost a year. Well anyways this is overall a great fish.
I have a 570 liter tank with red bellies and a large black pacu. He is 50 cm or bigger and I've seen him eat african cichlids, strawberries and feeder fish, but he is friendly with me.
I have got a Pond with 12 black pacus. The largest one of them is 45 cm and the others are not much smaller. It only took half a year to grow that size. I also have guppies, mollies. etc. in the pond and none of them ever got attacked by a pacu. But occasionally my kois eat one or two of the guppies. If you have got several pacus in your tank, you should build a pond for them. It's really easy to do and they withstand any temperature changes or water changes. My pond is filled with brackish water and the pacus have no problems with that. At day time the pond reaches very high temperatures and still they look happy and lively. Another cool thing about them is that they will jump almost half a meter out of the water to catch food I throw in, if they haven't been fed for a while.
My family and I have owned a black pacu for about three years now in a 1100 liter koi pond. We purchased him for only seven dollars at the local pet store who could no longed handle the foot-long fish. But we had the space, so he became part of our collection. He's always been a favorite of ours because of his gigantic size and koi-like personality. Although he's never really been a social fish, he's let us pet him in the past and once in a while would eat from our hands. Once, while cleaning out a pump, my mother found an actual tooth of his. Like a child's molar, only smaller and slightly more fragile. We've never had a problem with him consuming other fish. He's always prefered whatever plant-life we placed in the indoor pond or koi food. He's grown rather large off of it. He's grown over 45 cm in the last few years and if he grows anymore we're going to have to build him a larger pond.
I have five of these wonderful Black Pacu's. They are hearty feeders and not aggressive. They are all 60 cm in length, and love eating gold fish. They are in a 760 L tank, and live with two Oscars and a clown knife fish. They all get along well.
I have 4 Pacus: 3 Red Bellys and one Black. They are about 45 cm and 7 years old. I love them, they are so sweet. Their tankmates are 2 plecos, 2 Severums, and 1 Black Shark. They used to live with a little silver dollar and they treated him like their little baby. The Silver Dollar would follow them back and forth. The whole time I've had them they have never eaten another fish. I feed them Trout Chow, strawberries, tomatoes, and worms from the garden.