The Red Pacu Piranha (Piaractus Brachypomus), is not a real Piranha, despite belonging to the family Serrasalmidae, this is a herbivor and actually a colorful one, harmless, often also called red-bellied Piranha or Red Piranha (Pygocentrus nattereri), its genus (Piaractus) tells us more factual information as well as the actual species which is Brachypomus, it can grown up to almost 90cm, and would not be recommended as a private aquarium fish unless you have spare space in Sea World