Piranha Fish: Bites, Diet, Eating and US State Bans

Piranhas are toothy South American river fish. Wikipedia says the name now covers essentially all members of the subfamily Serrasalminae except the silver dollars (Metynnis), and estimates of the number of species run from fewer than 30 to more than 60. Most are 12 to 35 cm long; the red-bellied piranha (Pygocentrus nattereri), the largest living one and the most common in the pet trade (California Department of Fish and Wildlife), reaches 50 cm.

The teeth are the identifying feature: a single row of sharp, tightly packed, interlocking teeth in each jaw (Wikipedia). The black piranha has one of the most forceful bites measured in any vertebrate relative to its body mass.

The closely related pacus look similar. Wikipedia's Pacu article says pacus have squarer, straighter teeth with a slight overbite or a mild underbite, while piranhas have pointed, razor-sharp teeth in a pronounced underbite. A photo of the open mouth is the quickest way to separate them.

Much less than their reputation. Wikipedia describes them as basically regular fish with large teeth. They are omnivores that eat fish, plants, seeds and detritus, and research cited by Wikipedia found they school to protect themselves from cormorants, caimans and dolphins, not to hunt together.

Bites on people do happen, usually where people swim in shallow water near nests. Wikipedia says attacks typically cause minor injuries to the feet or hands, that fatal attacks are rare, and that when piranhas do feed on a human body it is usually someone who had already died, such as a drowning victim.

If you are bitten, clean the wound and see a doctor: the cuts can be deep and river water can carry infection.

In many states, yes. LegalClarity (updated 9 August 2026) lists 26 states that ban keeping piranhas: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Kentucky, Louisiana, Maine, Massachusetts, Mississippi, Nevada, New Mexico, New York, North Carolina, Oklahoma, South Carolina, Texas, Utah, Virginia and Washington.

• California: all piranha species are restricted animals that cannot be imported, transported or possessed without a permit (California Department of Fish and Wildlife)
• Florida: the whole subfamily Serrasalminae is a prohibited nonnative species, and no permits are granted even to zoos (LegalClarity, citing Florida Administrative Code 68-5.007)
• North Carolina: live piranhas of the genera Pristobrycon, Pygocentrus, Pygopristis and Serrasalmus may not be possessed (LegalClarity)

The reason is ecological. CDFW says a released piranha could eat native fish and amphibians and compete with them. Piranhas have turned up in several states and in Canada without establishing, and Florida eradicated them three times, in 1962, 1977 and 2009. CDFW asks anyone who finds one in California not to release it, to freeze it and to contact its Invasive Species Program. Local rules can be stricter than state law, so check with your state wildlife agency before buying one.

People in their native range do eat them. Wikipedia says piranhas are eaten as subsistence food and sold in markets, and that indigenous peoples use the teeth as carving and cutting tools. In the US you are unlikely to meet one to eat, since possession is banned in many states.

AquariumStoreDepot's care guide sets these basics for red-bellied piranhas:

• Tank: 100 gallons (379 litres) as the realistic minimum for a group of 4 to 6
• Group: at least 4, because smaller groups concentrate aggression on one fish
• Water: 75 to 82°F (24 to 28°C), pH 5.5 to 7.5
• Size and lifespan: 8 to 10 inches in aquariums (up to 13 in the wild), living 10 to 20 years
• Diet: shrimp, fish fillet and shellfish as staples; beef heart and chicken only as occasional treats
• Safety: use feeding tongs and know where the fish are before putting a hand in the tank

Research and drafting for this page were assisted by AI, and every figure was checked against the sources listed below on 25 September 2026. Where two sources disagree, both figures are given with their source.