The fish Pygocentrus piraya often calle the piraya piranha or San Francisco piranha, is a large, aggressive piranha from the São Francisco River basin in Brazil. It is one of the largest piranhas, reaching a maximum length of 50 cm in the wild, and is sometimes considered the most beautiful, with its orange to yellow belly coloration, silver eyes, and rayed fibrous adipose fin. Like most other piranhas, P. piraya is laterally compressed and roughly circular in profile, and bears a mouthful of very sharp teeth. The lower jaw is thick, strong, and protruding.