Red-bellied piranha

The red-bellied piranha is a silvery freshwater fish with a rosy, red-orange belly. It lives in the warm rivers, streams, and lakes of South America, in places like the mighty Amazon. Young piranhas start out silvery with dark speckles, and the belly turns red as they grow up.

Piranhas have a scary reputation, but the real fish is much calmer and shyer than the stories. Most of the time a red-bellied piranha is a scavenger and forager. It eats fruit and seeds that fall into the water, along with insects, water plants, small fish, and bits of animals that are already dead. During the rainy season, when food is everywhere, it happily munches on plants and bugs.

These fish love company and travel together in groups called shoals. For a long time people thought they swam in groups to hunt, but scientists discovered the opposite is true. The piranhas gather to keep each other safe, because plenty of bigger animals, like river dolphins, caimans, and large birds, would like to eat them.

A red-bellied piranha is usually about the length of a school ruler, and the biggest ones can grow to around half a metre. They have strong jaws and sharp, triangle-shaped teeth that are perfect for snipping food into pieces, a bit like tiny scissors.

Red-bellied piranhas are not rare. They live across a huge stretch of South America and are listed as Least Concern, which means there are still plenty of them swimming in the wild. They are a shy, misunderstood fish that plays an important part in keeping their rivers clean and healthy.