Piranhas can bite humans, but they are not typically dangerous to people. Fatal attacks are extremely rare, and most incidents involve a single nip or small bite rather than sustained attacks on a person. Key points

• Most species of piranha have strong jaws and sharp teeth, which can cause painful injuries if a swimmer disturbs them or if the water is crowded and visibility is low. However, outright predation on humans is uncommon.

• Attacks on humans, when they occur, are usually linked to high-stress situations such as protecting nests, limited space during dry seasons, or aggressive feeding frenzies in confined waters. In these cases, injuries are often bites to extremities like feet or hands, not guaranteed fatalities.

• The Red-bellied Piranha is frequently cited in discussions of piranha behavior and is associated with some human-bite incidents, but even then most encounters are non-lethal and non-predatory toward people.

• Public-facing sources and experts generally describe piranhas as not naturally inclined to hunt humans, and “man-eater” portrayals are largely sensationalized. Still, disturbances in water and environmental conditions can elevate risk in certain contexts.

Practical safety tips

• Avoid splashing or thrashing in water that is known to host piranhas, especially near river mouths, shallow habitats, or fishing areas where fish are concentrated.
• Stay calm if piranhas are present; sudden movements can attract attention and trigger bites.
• If swimming in warm freshwater regions where piranhas are native, prefer zones with clear water and avoid nests or dense vegetation that may harbor groups.

If you’d like, I can summarize these points with citations to specific sources or tailor safety guidance to a particular location or scenario.