Amazing Piranha fish
A piranha or piraña is a member of family Characidae in order Characiformes, an omnivorous freshwater fish that inhabits South American rivers. In Venezuela, they are called caribes. They are known for their sharp teeth and a voracious appetite for meat.
Piranhas belong to the subfamily Serrasalminae, which also includes closely related omnivorous fish such as pacus. Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis and Serrasalmus are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be monophyletic, it should be restricted to Serrasalmus, Pygocentrus and part of Pristobrycon, or expanded to include these taxa plus Pygopristis, Catoprion, and Pristobrycon striolatus. Pygopristis was found to be more closely related to Catoprion than the other three piranha genera. The total number of piranha species is unknown and contested, and new species continue to be described. Estimates range from fewer than 30 to more than 60.
Piranhas are found in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paraná, and the São Francisco River systems. Some species of piranha have broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have more limited distributions.
Aquarium piranhas have been introduced into parts of the United States with specimens occasionally found in the Potomac River, Lake of the Ozarks in Missouri and even as far north as Lake Winnebago in Wisconsin, although they typically do not survive cold winters. Piranhas have also been discovered in the Kaptai Lake in south-east Bangladesh. Research is being carried out to establish how piranhas have moved to such distant corners of the world from their original habitat. It is anticipated that some rogue exotic fish traders have released them in the lake to avoid being caught by anti-poaching forces.
Myths about Piranha fish
There are various myths about piranhas such as how they can dilacerate a human body or cattle in seconds. These myths refer specifically to Serrasalmus nattereri, the red-bellied piranha. A recurrent myth is that they can be attracted by blood and are exclusive carnivores. A Brazilian myth called "piranha cattle" states that they sweep the rivers at high speed and attack the first of the cattle entering the water allowing the rest of the group to traverse the river. These myths were dismissed through research by Helder Queiroz and Anne Magurran and published on Biology Letters. Nevertheless, a study in Suriname found that piranhas may occasionally attack humans, particularly when water levels are low.
Piranhas are normally about 14 to 26 cm long (5.5 to 10.25 inches), although some specimens have been reported to be up to 43 cm (17.0 inches) in length.
Courtesy : http://en.wikipedia.org/wiki/Piranha
Amazing Piranha fish Images