INTRODUCTION

"A fish only a foot long....They are the most ferocious fish in the world. Even the most formidable fish, the sharks or the barracudas, usually attack things smaller than themselves. But the piranhas habitually attack things much larger than themselves." (Theodore Roosevelt, in his 1914 book, "Through the Brazilian Wilderness" - Dr. George S. Myers, Piranha Book, 1977)....And so we commence the discussion of the fish we commonly call a piranha. This misunderstood fish has been feared by countless people in the United States and around the world, often without reason. Are they dangerous fish? Can they live in our waters? Perhaps the reader visiting this web site will come away with a better understanding of this legendary fish. Maybe even accepting the premise that this fishes reputation may someday be relegated to the myths and legends of monsters we have once believed in to be fact.

HOW DO MODERN SCIENTIST'S VIEW PIRANHAS TODAY?

«Piranhas» or «caribes» as they are commonly known, are the most notorious living aquatic animals in South America. The great speculation, tales with nonsense and fantastic stories grown around them exceeds their scientific knowledge. Their high diversity and predatory habits make them an important part of our aquatic communities. So far more than 30 nominal species have been recognized belonging to 4 genera: Pygopristis, Pygocentrus, Pristobrycon and Serrasalmus. The last one include de majority of the species.

 Machado-Allison (1982, 1985), recognized the monophyletic origin of this clade. However, some inner relationships still to solve. For example the condition of Pristobrycon, with species with pre-anal spines and no ectopterygoid teeth ( P. striolatus), and species with those conditions such as P. calmoni. Recently, Fink & Machado (1992), described 3 new species for Brazil and Venezuela: Pristobrycon careospinus, P. maculipinnis and Serrasalmus gouldingi. This report presents only in the Venezuelan species. We recognized 4 genera and 16 species in Venezuela. Pygopristis (P. denticulata); Pygocentrus (P. cariba); Pristobrycon (P. calmoni, P. careospinus, P. maculipinnis and P. striolatus); and Serrasalmus (S. altuvei, S. eigenmanni, S. elongatus, S. gouldingi, S. irritans, S. manueli, S. medinai, S. nalseni, S. neveriensis, and S. rhombeus). However, there are at least 2 more new(?) species that are share with the Amazon Basin of Brazil and Colombia. Also, we discuss aspects of their distribution on the Orinoco, Amazonas, Essequibo and Caribe Basins, and information on the feeding habits.

DISCUSSION

Any species of piranha should be considered potentially dangerous even though there is no record of attacks resulting in death by these fish on live humans. Reported injuries are those from fishermen (carelessly removing the fish from hook), or areas where the fish have been conditioned to a ready food source (ie., where fish are cleaned on a regular basis and entrails are thrown in the water) or recovery of drowned victims who were later skeletonized by these fishes. Piranhas are scavengers by nature, a finned health squad (Schulte 1988).

Historically, piranha attacks on live humans were based on over exaggerated stories of  Spanish conquistadors being eaten alive by these fish. An examination of historical accounts reveals that the fish attacked the conquistadors because of their wearing red trousers and blood in the water. Tales of their being eaten alive was actually more realistically attributed to the soldiers drowning then later being skeletonized by piranhas (Myers 1972, Schulte 1988 and  Schleser 1997). (SEE Myths about Piranhas started by Roosevelt).

My own experience with a piranha bite (which required 3 stitches) happened while transporting the fish from one aquarium to another (1973). The fish bit through the net being used to transport it, then landing in my hand. The bite was painless but bled copiously. It is for this reason the home aquarist should carefully handle their fish. It was the only time I have ever been bitten and it will be (hopefully) the last time. The pain itself lasted for about 6 months and took long for me to be able to bend that finger freely without pain. The piranha teeth may look small but that is not what makes them dangerous. It is the powerful musculature and razor sharp teeth with the ability to snap quickly and repeatedly that makes them capable of clipping off a portion of your flesh. Including bone and all depending on your fishes size.

FORBIDDEN BY STATE LAWS - United States

The map left is a replication of the written information provided by the American Fisheries Society (1996) which reported areas that piranhas could establish viable populations by using the mean temperature of January as the coldest time period. This cold indicator would give biologist a better idea in what parts of the United States piranhas could be established during the coldest time of the year. The coloration of the above map is my own interpretation of that information applied to this map.

The map left is the current list of States prohibiting piranha possession. Some of these states that are not prohibiting piranha, may require a permit to possess them, however, it is very unlikely any single one person could secure such a permit. Majority of these permits are approved for zoological parks and museums. Some States (State of Florida for example) don't even allow public exhibit of piranhas for fear they could escape from the public aquarium! Some States have stiff fines for possession of piranhas (ex: $500 per fish confiscated). See chart below for city, county, State ordinances.

In researching this data, some States and other countries are indeed promulgating new rules that will probably change this in the year 2003-2008. Recently Channa species are prohibited (USFW  2002) from importation into the United States. Some states mandate a stiff fine (5 years imprisonment and $5,000 fine) for possession of this fish. Even South America is not free from transplanted fish that don't belong there. Trout (Salmo species) have been introduced by conservationist to enhance sport fishing!

This has produced problems with whirling disease (Heximita) and other non-native parasite problems. Piranhas are also introduced in non-native habitat range much like how they are introduced here in the United States. This has led to a mixture of species that is unnatural and caused scientists to pause and examine the origin when such fish are captured.

PACU HARMLESS OR A MENACE?

I received many letters in the past about, how unfair states laws are. Yet hobbyists ignore the basic fact their peers are creating the problem in the first place by releasing unwanted fish. I hope home aquarists who want to collect piranhas as pets can see what happens when they ignore common sense and why laws are then proposed prohibiting their piranha or other predatory fish. 

The map above is data collected from newspapers and personal correspondence from aquarists across the USA including information gathered from Nonindigenous Aquatic Life (Nico 2002) In one or two states the fish and wildlife officials misidentified the fish as a pacu instead of an actual piranha (NICO, 2000). The idea behind my map above is to illustrate how foolish aquarists are by releasing unwanted pet fish. This species is also being found in other countries including Australia. Unfortunately, they are being misidentified as piranha.

WHY PIRANHAS ARE PROHIBITED

The capture of pacus and the media frenzy that follows proclaiming this fish piranha, unfortunately, lead to laws prohibiting piranhas from public fear even though the identification is usually wrong. But that in itself should warn people who keep piranhas as pets that their actions could promulgate additional laws to prohibit their pet fish. The capture of vegetarian pacus in open lakes, rivers, streams has been the driving force to prohibit piranhas in most of the United States. OPEFE in the past has received many donated red-belly pacus that have grown to large for the home aquarium. Pacus have actually been reported in nearly every lake, river, canal in the United States. Most recently two more pacus not reflected in the map above have appeared in Utah and Tennessee (The Greenville Sun, 2000). If this continues it will not surprise me if statutes are enacted to prohibit pacus from being sold or possessed by the home aquarists. According correspondence between myself and Dr. Antonio Machado-Allison (University of Venezuela), he states, "Pirañas in our aquarium dies frequently when the temperature get below 23 C." Large winter kills of piranhas of red piranhas are reported from the upper and lower reaches of Paraguay (south of Ascunción, Paraguay). The temperature that reportedly drops below 40°F (4.4ºC) during their winters. Interestingly enough, piranha populations have never been discovered in our close neighbor, Mexico. It is my understanding, though not verified that piranhas are illegal in that country. Germany which is one of the colder countries than America, also prohibits piranha. India, Malaysia, Vietnam are countries that recently prohibited piranhas. Vietnam reported captures in their waters, but my communication with their authorities in trying to collect data regarding those captures has been unanswered and unverified. Even still conservationist fear the legendary piranha with good reason, people must stop being irresponsible in their actions when it comes to deposing of a pet. Release of non-natives hurts everyone as well as future generation of native fish a lesson U.S. fish conservationists are learning after they introduced game fish that were non-native throughout the  United States.

There are a few recorded cases of piranha introduction in U.S. waters in over 60+ years this fish has been available to the home aquarist (See MAP above). That in itself is a miracle considering how long these fish have been available to the pet industry. In Hawaii on the island of Oahu (Wahiawa Reservoir) in 1992 a mature female Pygocentrus nattereri was captured in 1993 (NICO, 2000). There was no indication the species had become established (Radke 1995 and NICO, 2000). The piranha was quickly destroyed. Four other instances were found on the mainland in Florida where a small population (S. rhombeus) was found in Monkeyland amusement park pond and 3 Pygocentrus nattereri were found as single captures in 1974 Dade County and Palm beach county 1979, which resulted in the lake being treated with rotenone killing all fishes present including all native fishes. However, just as recent (1998) a Pygocentrus nattereri (identification verified) was captured in Canada in a lake. That specimen was obviously a tank raised piranha according to Dr. W. L. Fink who spent time examining the fish (pers com. Fink, 1998). Piranhas have been reported captured in ten states, including Florida, Hawaii, Massachusetts, Michigan, Minnesota, Ohio, Oklahoma, Pennsylvania, Texas, and Virginia (Nico, 2000). However, few were actually documented as a piranha and might have been a pacu instead.

The author (Magallanes) strongly recommends that no species of Serrasalminae be kept in outdoor pools regardless of how noble or great the idea is. The risk is not worth it.

Below is a partial list of non-native Characidae found in U.S. waters:

1. Metynnis sp. metynnis

2. Moenkhausia sanctaefilomenae redeye tetra

3. Myleus rubripinnis redhook pacu

4. Paracheirodon innesi neon tetra

5. Piaractus brachypomus pirapatinga

6. Piaractus mesopotamicus small-scaled pacu

7. Pygocentrus nattereri red piranha

8. Pygocentrus or Serrasalmus sp. unidentified piranha

9. Serrasalmus rhombeus white piranha

REFERENCES 

• Oral presentations - IX Meeting of the Neotropical Ichthyological Association, Antonio Machado-Allison and William L. Fink, Universidad Central de Venezuela, Museo de Biologia, Apto Correos 47058, Caracas, 1041-A. Venezuela

• Fink, William L. 1993. Revision of the Piranha Genus Pygocentrus (Teleostei, Characiformes). Copeia 3:665-686.

• Fuller, P. L., L. G. Nico and J. D. Williams. 1999. Nonindigenous Fishes Introduced into Inland Waters of the United States. American Fisheries Society, Bethesda, Maryland.

• Saint-Paul, Ulrich, Jansen Zuanon, Marle A. Correa, Marcelo Garcia, Nidia Fabre, etc. March 2000. Fish Communities in Central Amazonian White- and Blackwater floodplains. Environmental Biology of Fishes 57:235-250.

• Sazima, Ivan and Francisco Machado. 1990. Underwater Observations of Piranhas in Western Brazil. Environmental Biology of Fishes 28:17-31.

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UPDATED: 07/09/2009