Feeder goldfish are a popular choice for feeding piranhas, although they contain a B vitamin inhibitor that may stunt growth and shorten the fish's life span.
Pygopristis was found to be more closely related to Catoprion than the other three piranha genera (Freeman et al.
The most common piranha is the Pygocentrus nattereri, or the red-bellied piranha.
Some piranha species are abundant locally and multiple species often occur together (Freeman et al.
Traditionally, piranhas, pacus, and silver dollars comprised the Serrasalminae subfamily of the Characidae family (Nelson 1994).
Recent research, however, suggests that this is actually used as a defense mechanism against the piranha's natural predators, such as river dolphins, caimans, and giant pirarucu (Edward 2007).
Locals also use piranha teeth in tools and weapons.
The number of piranha species is about 24, and new species continue to be described.
Pacu and piranha are distinguished from each other by their teeth and jaw alignments.
Nonetheless, the unique form and behavior of piranhas add to the wonder of nature for people.
Piranhas are found only in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paranб river basins (such as the Pantanal), and in the Sгo Francisco River systems.
Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis, and Serrasalmus are considered to be true piranhas, due to their specialized teeth.
In 1988, it was stated that fewer than half of the approximately 60 nominal species of piranhas at the time were valid.
A few piranha species appear in the aquarium trade (Freeman et al.
Serrasalminae or Serrasalminidae means "serrated salmon family" or "saw salmon family," and is a name that refers to the serrated keel running along the belly of piranhas (and pacus) in this family.
Local children swim in South American rivers inhabited by piranha.
The pointed, razor-sharp teeth of piranhas are in a pronounced underbite.
The piranha is renowned and portrayed as a vicious species of fish, hunting in large schools.
Piranhas occasionally bite and sometimes injure bathers and swimmers, but truly serious attacks are rare and the threat to humans has been largely exaggerated (Freeman et al.
Piranhas are normally about 15 to 25 centimeters long (6 to 10 [[inches), although reportedly individuals have been found up to 41 centimeters (24 inches) in length PZ 2007).
Piranhas can be purchased as pets in some areas; however, they are illegal in some parts of the United States, such as the State of Washington (Magallanes 2007).
Ecologically, piranhas are important components of their native environments.
Piranhas prefer a darker environment with a lot of plant cover, as they become agitated when denied appropriate cover.
Piranha are a popular food in areas in which they inhabit.
Piranhas can be bought fully grown or as babies, often no bigger than a thumbnail.