Piranhas are freshwater fish known for their sharp teeth and powerful jaws. They are primarily found in the rivers and lakes of the Amazon Rainforest in South America. Piranhas typically grow to about 12 to 24 inches in length and are often recognized for their distinctive, triangular-shaped bodies. These fish are carnivorous and often hunt in groups, which helps them catch larger prey. While they have a reputation for being aggressive, most species are not dangerous to humans. Piranhas play an important role in their ecosystem by helping to control fish populations and clean up dead animals.