- Common Name
- Genus Species
- Serrasalmus spp.
- Piranhas have a robust, narrow body, a blunt head, and strong jaws with triangular-shaped, razor sharp teeth. Piranhas tend to be silvery with red-pigmented patches.
- Typical size is 20.3 to 30.5 cm (8 to 12 in.), although adults of some species grow larger
- Omnivorous; feeds on fish, crustaceans, aquatic invertebrates, seeds, fruit, carrion, and plant matter
- Oviparous (egg laying)
- Piranhas are generally found in South American rivers including the Sao Francisco, Paraguay, and Orinoco rivers
- Fresh water rivers
- Global: No data
- IUCN: Not listed
CITES: Not listed
USFWS: Not listed
- Piranhas are well known for their razor sharp teeth, and have a reputation for having voracious appetites. Although they are known to occasionally attack large animals, the reputation is greatly exaggerated. Most adult piranhas - depending on the species - eat fruit, seeds, and fish. Some have been found with bird fragments, snakes, and small mammals in their stomachs. Young piranhas may eat copepods, crustaceans, and insects.
- Piranhas may feed more aggressively when their normal food resources become scarce. Water levels of their river homes fall during the dry season. Piranhas may become trapped in stagnant pools for weeks. When all of the food in these pools is consumed, piranhas may eat anything that enters the water.
- Five species are considered potentially dangerous to humans: Serrasalmus piraya, S. nattereri, S. niger, S. rhombeus, and S. eigenmanni , but piranha attacks on people are extremely rare. According to Dr. Herbert R. Axelrod, in his Atlas of Freshwater Aquarium Fishes, "In 25 years of travel and fishing in almost every river system in South America, nearly all of which had schools of piranha, I NEVER was bitten, nor did I ever meet anyone who was bitten...nor did I ever meet anyone who even knew anyone who was bitten by a piranha...and these are mostly Indians who live on the river and swim in it every day."
- For more information about bony fishes, explore the Bony Fishes InfoBook.
Ecology and Conservation
Piranhas' natural predators include crocodiles, Amazon river dolphins (botos), and herons. With the decline of these predators, piranha populations are increasing in certain rivers. Humans also hunt piranhas for their meat and for the pet trade. It is legal to have piranhas as pets in some areas. Of course, aquarists must take care while handling piranhas to avoid receiving a serious bite.
Axelrod, H.R., Burgess, W.E., Pronej, N. and Wall, J.G. Dr. Axelrod's Atlas of Freshwater Aquarium Fishes. Neptune City, NJ. T.F.H. Publications, Inc. 1997.