Piranha Fish

 Myths and Facts

Piranhas are a type of razor-toothed carnivorous fish that inhabit the rivers and lakes of South America. These fish have earned a reputation for being ferocious, largely due to their depiction in popular movies such as *Piranha* (1978). However, most species of piranha are either scavengers or feed on plant material, showing that their fearsome image may be somewhat exaggerated.

Physical Characteristics

Most piranhas measure no more than 60 cm (about 2 feet) in length. Their color varies from silvery with orange undersides to nearly black. These fish possess deep bodies and sharp bellies, along with large, often blunt heads equipped with strong jaws that contain sharp, triangular teeth which fit together in a scissor-like manner.

Notable Species

People Also Read-arowana fish

- Red-Bellied Piranha: 

The red-bellied piranha (*Pygocentrus nattereri*) is one of the most infamous species, known for its strong jaws and sharp teeth. Found in the Amazon River, this species can grow up to 50 cm (about 20 inches) long and often hunts in groups of over 100 during low water seasons. These groups can enter a feeding frenzy if they attack a large animal, although such instances are rare. Red-bellied piranhas prefer prey that is either slightly larger than themselves or smaller. They use their excellent hearing to communicate and locate prey.

- Lobetoothed and San Francisco Piranha: 

The lobetoothed piranha (*P. denticulata*) primarily inhabits the Orinoco River basin and lower Amazon tributaries, while the San Francisco piranha (*P. piraya*) is native to Brazil's San Francisco River. Both of these species can pose a danger to humans, though attacks are infrequent.

Piranha Behavior

Although piranhas are known for their attraction to the smell of blood, most species scavenge more than they kill. Some 12 species called wimple piranhas (*Catoprion* genus) survive solely on nipping at the fins and scales of other fish, allowing the prey to swim away and heal.

Classification

Ichthyologists often distinguish between carnivorous "true piranhas" and the vegetarian members of the Serrasalminae family. 

True piranhas typically include three species within the Pygocentrus genus: P. piraya, P. nattereri, and P. cariba. Other classifications expand the group to include four genera: Pristobrycon, Pygocentrus, Pygopristis, and Serrasalmus, based on their sharp triangular teeth. There are still other classifications that either include additional genera, such as Catoprion, or exclude Pristobrycon, as it may not be monophyletic—meaning not descended from a single common ancestor.

Piranhas are fascinating fish with a complex and varied ecology. While they can be dangerous, they play an important role in the ecosystems of South American rivers and lakes.