Characins: Characiformes

Physical characteristics: Red-bellied piranhas have an average length of 6 to 8 inches (15 to 20 centimeters) but can grow to 12 inches (30 centimeters). The belly, the throat, the pectoral (PECKter-uhl) fins, or the front pair, the pelvic fins, or the rear pair, and the anal fins are bright red. The sides are often pale brown to slightly olive, and the back is bluish gray to brownish. The powerful jaws have sharp, triangular, interlocking teeth.

Red-bellied piranhas are kept as aquarium fish. This activity is illegal in some parts of the United States to prevent irresponsible hobbyists from releasing the piranhas into the wild, where they can multiply and prey on native fishes. (©David M. Schleser/Nature's Images, Inc./Photo Researchers, Inc. Reproduced by permission.)

Geographic range: Red-bellied piranhas live in South America.

Habitat: Red-bellied piranhas live in creeks and ponds. They prefer areas with dense plant life.

Diet: Red-bellied piranhas eat other fishes but also scavenge for food and eat insects, snails, worms, and plants.

Behavior and reproduction: Red-bellied piranhas look for food mainly at dusk and dawn. After a courtship display involving swimming in circles, the female deposits layers of eggs on plants in the water, and the male fertilizes them. The male guards the egg masses and fans them with his fins until the eggs hatch in nine or ten days.

Red-bellied piranhas and people: Red-bellied piranhas are kept as aquarium fish. This activity is illegal in some parts of the United States to prevent irresponsible hobbyists from releasing the piranhas into the wild, where they can multiply and prey on native fishes. People who live along the rivers inhabited by red-bellied piranhas catch and eat them.

Conservation status: Red-bellied piranhas are not threatened or endangered. ∎