Red-bellied piranha

Class: Actinopterygii
Order: Characiformes
Family: Serrasalmidae
Genus and Species: Pygocentrus nattereri
  • Silver fish with orange-red blush to its belly swimming underwater
  • Silver fish with orange-red blush to its belly swimming underwater
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Red-bellied piranha

True to their name, red-bellied piranhas are red on their undersides from chin and cheeks to belly. They are important scavengers in their Amazon River ecosystems, and a large part of their diet comes from fins nipped from the tails of larger fish. They can grow to be a little over a foot long (30.5 centimeters) and weigh up to 4 pounds (1.81 kilograms). They tend to travel in schools of 20 or more individuals.

Physical Description

Red-bellied piranhas are red on their undersides from chin and cheeks to belly. The head and body are various shades of gray; their sides are flecked with bright silver scales. The piranha's distinctly rounded and snub-nosed profile serves a function. Beneath the high forehead are powerful muscles that attach to a short, stout lower jaw fitted with triangular, razor sharp teeth, which interlock neatly with a matching set above. This design allows piranhas to bite down with incredible force and shearing ability. However, these formidable teeth are not usually visible, being covered by thick, fleshy lips.

Size

They can grow to be a little over a foot long (30.5 centimeters) and weigh up to 4 pounds (1.81 kilograms).

Native Habitat

Red-bellied piranhas are found throughout the low elevation regions of the Amazon River basin. They inhabit both still and moving sections of the vast fresh-water Amazon River basin system.

Food/Eating Habits

In the wild, a good portion of their diet consists of fins nipped from the tails of larger fish. Additional items on a piranha's menu can include bits of flesh, whole small fish, insects, aquatic invertebrates and occasionally, plant material in the form of figs and other ripe fruit. At the Smithsonian's National Zoo, red-bellied piranhas receive a gelatin diet (a mixture of greens, proteins and micronutrients in a gelatin base), smelt, shrimp, herring and earthworms.

Social Structure

They tend to travel in schools of 20 or more individuals.

Reproduction and Development

Red-bellied piranha reproduction begins with a courtship display involving swimming in circles. These piranhas are nest builders, with males creating bowl-shaped crevices in the sediment where eggs are placed. The eggs are laid in clusters and are attached to submerged aquatic vegetation. It is theorized that spawning could potentially correlate to the Amazon's wet season.

Sleep Habits

Smaller piranha search for food during the day, while larger fish tend to be more active at dawn and dusk.

Lifespan

Red-bellied piranhas have a lifespan of 10 years or more.

This species is relatively common throughout its range.