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Red Piranha Pygocentrus nattereriLatest Reader Comment - See More This is a great article and very well written -- the only thing I would change is when you put the elongatus piranha get a very powerful lower jaw....
I... (more) Philip Jabra The piranha's are members of the Characidae (or Characin) family, a large family of more than 1200 species, including some of the most widespread and popular aquarium fish like the all the common tetra's and hatchetfish.Red Piranha Contents The piranhas belong to a sub-family called the Serrasalmidae (serra means 'saw', 'sawed' or 'serrated', salmus means 'salmon'), a name based on the fact that all members have a sharp, serrated keel running over the belly to make the body more streamlined (for faster swimming). How many members this subfamily consists of is not certain because there is a lot of debate over the proper scientific classification. Besides that, new unidentified species, regional varieties and color forms are discovered, and new and/or updated research data (concerning DNA, parasites, morphology etc.) is published on a fairly regular basis. For what is known, there are at least more than 40 different species (Silver Dollars, Pacu's, Whimple Piranha's etc. included). For more Information on keeping this fish see: |
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Habitat: Distribution / Background
The recent discovery of a number of new species or subspecies makes proper identification and classification an even more difficult enterprise. For example, the species formerly known as Serrasalmus niger is nowadays known as Serrasalmus rhombeus, and there are many indications that this species is in actuality a complex of similar looking, but different fish (depending on the collection point, among other factors), which means the Serrasalmus rhombeus-'complex' eventually may be split up in separate species if scientific research confirms this theory. The same applies to Serrasalmus spilopleura: this species may actually be a complex of similar species with subtle differences in shape, color and locality (for example, in the pet trade, some specimen are sold as Gold Spilopleura, others as Purple Spilopleura, obviously because of their coloration).
Serrasalminae Classification (per Nelson, 1994)
Phylum: CORDATA (animals with brains)
Subphylum: VERTEBRATA (animals with backbones)
Superclass: GNATHOSTOMATA (jawed vertebrates)
Class: ACTINOPTERYGII (ray-finned fishes)
Division: TELEOSTEI (true bony fishes)
Super order: OSTARIOPHYSI (bony fishes)
Order: CHARACIFORMES (characin forms)
Family: CHARACIDAE (characins)
Subfamily: SERRASALMIDAE ('serrated salmon' family)
Genera: PYGOCENTRUS: Caribe / 'True' Piranha's
SERRASALMUS: Pirambeba's
PRISTOBRYON: Pirambeba's
PYGOPRISTIS: Pirambeba's
CATPRION: Wimpel Piranha's
COLOSSOMA: Tambaqui / Pacu's
ACNODON: Schaapsnuitpacu's
OSSUBTUS: Papagaaipacu's
METYNNIS: Silver Dollars
MYLEUS: Silver Dollars
MYLOSSOMA: Silver Dollars
As mentioned, piranha's can be divided into a number of different genera, all with different visual traits. Members from the genus Pygocentrus are all recognizable by the convex shape of their head and massive bulldog-like lower jaw (more powerful and muscular than most Serrasalmus-species). This reflects their diet: besides being scavengers, if necessary all Pygocentrus-species are full blown predators as well, that actively give chase to their prey.
Serrasalmus-piranha's have a more concave head shape, and less powerful lower jaws. A number of species feed themselves mainly on fins and scales of other fish, and even nuts and fruits, and therefore they do not need the same muscle packed lower jaw to rip through skin, muscle and bone. This does not apply every species of this group, however: Serrasalmus rhombeus, manueli and elongatus, to name a few, are true predators when adult, and do have very massive and powerful jaws as well. But regardless of their diet, all Serrasalmus-species share the piranha's unmistakable trademark feature, the triangular, razor sharp teeth: large ones in the lower jaw and smaller ones in the upper jaw. When the mouth is closed, the teeth from both jaws fit exactly, comparable to a bear-trap. This enables them to slice off pieces of meat or fins or scales, literally taking apart their prey piece by piece.
Social behavior
In the wild, piranha's from the genus Pygocentrus live in large shoals, roaming the South American rivers. This situation is impossible to imitate in captivity, but even in a tank they will show some traits of their wild behavior, provided they are kept under proper conditions.
First of all, most shoals will have one or more dominant animals, depending on the size of the shoal: the leader(s) of the pack. Even though the fish will often hang out together, in crucial moments the dominant fish will show its might. In most cases, the alpha-animal will be the largest, most aggressive and bold specimen, first at feeding sessions and owning and guarding the best spots in the tank (the spot with the best view, the best place during feeding time, in the current from a powerhead). Any unwilling 'servants' will be corrected instantly by aggressive behavior, chasing or even inflicting wounds.
A group of Pygocentrus piranha's lives in a state of constant fear and mutual mistrust, even when all seems calm: the animals are all capable of severely wounding or even killing each other. To survive, the fish must always know where the others are, in what their states of mind they are, and how they might act the next moment. Letting your guard down may turn out fatal.
This behavior may be a partial explanation why many captive pirana's are relatively skittish and nervous, despite their fiercesome reputation. One moment of carelessness may mean the end of your life, even more in the wild, where piranha's are part of the diet of many predators, like jaguars, caimans, boto's (freshwater dolphins) and other, larger predatory fish, which live there in abundance. And piranha's are even preyed upon by their own relatives, especially amongst the young and during the dry season, when the amount of food is increasingly limited, and the fish are frequently trapped in increasingly small puddles. Juvenile piranha's have to face even more natural predators, and are even targeted by large insects and crustaceans. Most captive piranha's are less skittish and shy when they live in a tank with enough places to hide and dimmed lights. It makes them feel more at ease and secure, which will be reflected in their behavior: the fish will be more active, swim around more freely , and behaving in a more 'natural' way.
In the wild, the staple diet of the carnivorous Pygocentrus piranha species consists of fish. They catch their prey by active chasing, or by ambushing. Besides fish, they also eat insects, crustaceans, birds that have fallen into the water, and sometimes even mammals, reptiles or amphibians: basically anything that has attracted the attention of a hungry shoal, and is unable to leave the water in time. It is observed that shoals of Pygocentrus cariba congregate under trees where groups of birds are nesting. Somehow, the fish know when the young birds have hatched: they patiently wait under the trees for chicks falling in the water behavior that is remarkably similar to what Alligators do in the Everglades. And in times when prey animals are hard to find, piranha's will even supplement their diet with fruits, nuts and seeds when prey animals are hard to find, highlighting that these fish are very well adapted to cope with whatever circumstances their natural habitat throws at them.
Most larger animals that are attacked, are weakened, sick or injured: even a large shoal of piranha's will only attack a healthy animal on very rare occasions: during the dry season, when moving around freely is as good as impossible and food is scarce. Cannibalism amongst piranha's is not unusual during this period, and many others fall victim to predators looking for an easy meal. And perhaps also during the mating season, when aggression levels are at their highest. By weeding out the weaker animals, piranha's have the same task as the vultures or hyena's of the savannah: they are the health police of their habitat. Piranha's are attracted by splashing or the erratic movement of an animal in distress. Once they start feasting on their prey, other piranha's rush to the scene, drawn by the splashing of the victim, the blood and the noises and disturbance caused by the frenzied piranha's that are already feasting.
- Scientific Name: Pygocentrus nattereri
- Social Grouping: Solitary - Although they live in groups in the wild, in captivity they are best kept singly.
- IUCN Red List: NE - Not Evaluated or not listed
All piranha-species have a powerful, high, thick but laterally compressed body shape, with keel-like edges running over the upper part of the body from head to dorsal fin, and on the lower body running over the belly. Together with a large and powerful large tail and a body covered with very small scales, their streamlined bodies make them very fast and agile swimmers. The oddball in the family, shape wise, is Serrasalmus elongatus, the Elongated or Pike Piranha. This species has a salmon-like, elongated and slender body, but with the same powerful, well developed tail. It is said to be the fastest swimmer of all piranha species.
Unlike many fish-species, piranha's have a small adipose fin between tail and dorsal fin. This feature is characteristic for the Characin-family, although members from some other families, like catfish, have an adipose fin as well.
Their predatory lifestyle is reflected by large eyes and a large nose with big nostrils to maximize the water inflow. They have a very acute sense of smell: in their natural habitat, murky rivers in South-America, even more darkened by overhanging vegetation, scent is their main way of tracking down their prey.
- Maximum Size: 12.0 inches (30.48 cm)
- Aquarium Hardiness: Moderately Difficult - Although these fish are fairly hardy, aggression often leads to injury which can shorten the lifespan of this fish in the home aquarium.
- Aquarist Experience Level: Advanced
- Diet Type: Omnivore
- Flake Food: No
- Tablet Pellet: No
- Live foods (fishes, shrimps, worms): Most of Diet
- Vegetable Food: Some of Diet
- Meaty Food: Most of Diet
- Feeding Frequency: Daily
- Water Changes: Bi-weekly
- Minimum Tank Size: 100 gal (379 L)
- Substrate Type: Any
- Lighting Needs: Moderate - normal lighting
- Temperature: 73.0 - 82.0° F (22.8 - 27.8° C)
- Range ph: 6.0-7.5
- Hardness Range: 10 - 20 dGH
- Brackish: No
- Water Movement: Moderate
- Water Region: All
With the exception of a few species (like
Serrasalmus spilopleura
,
Serrasalmus maculatus
and
Serrasalmus geryi
), piranha's from the genus Serrasalmus are solitary fish. In general, they will not tolerate other fish in their tank, and are very aggressive and territorial. Their behavior in the wild is, due to lack of research, largely unknown. What we know is that Serrasalmus rhombeus sometimes travels and feeds in loose shoals in the wild, but prefer a solitary lifestyle. This may be due to environmental factors (such as the drying up of rivers during the dry season forcing the fish to share their constantly decreasing living space), and/or during the mating season.
Also known is the fact that juveniles from many Serrasalmus-species look very different from their parents, and this has a specific reason: cannibalism is very common amongst piranha's, and the younger they are, the more species prey on them. Many juveniles look like adult Pygocentrus piranha's (in particular: a red coloration of the lower body, ie. Serrasalmus medinai en Serrasalmus sanchezi), and live in their shoals. This behavior is called mimicry. Living in the middle of a shoal of larger, similar fish has certain advantages for the juveniles: not only does a large shoal provide protection against predators, it also offers a steady supply of food to the growing up piranha's. Young piranha's are also parasitic fin nippers, and will not hesitate to eat the fins of the fish in their "host" shoal to supplement their diet. When they get older, they usually leave the shoal and start living solitarily.
- Venomous: No
- Temperament: Aggressive - This fish sometimes appears suprisingly skitish in the home aquarium. The school of piranha is incredibly hierarchal and there will be a clear chain of command. Although the sturdiest of tankmates may survive alongisde this species, it is probably best to just go for a species tank.
- Same species - conspecifics: Yes
- Peaceful fish (): Threat
- Aggressive (): Threat
- Slow Swimmers & Eaters (): Threat
- Shrimps, Crabs, Snails: Safe - not aggressive
- Plants: Safe
Determining the gender of piranha's is considered almost or all together impossible by most piranha experts, because there are no visible differences between the genders (in other words, piranha's are not sexually dimorphic). The general consensus is that the only more or less fool-proof method to sex piranha's is to observe them during spawning. It is true that adult female specimen tend to be thicker due to the eggs they carry, it nonetheless is an unreliable method to tell both genders apart, as well-fed males are often just as thick.
The only known exceptions to this sexual dimorphism are the Wimpel Piranha (Catoprion mento), of which males and females are easy to tell apart, and possibly the Five-Cusped Piranha (Pygopristis denticulata).
See the description of egg laying fish in Breeding Freshwater Fish.
- Ease of Breeding: Difficult - The first challenge is finding a suitable breeding pair. Sexing is unreliable, although the thickness of the fish has been suggested to indicate gender. Frequent, large water changes should induce breeding as these fish believe the rainy season has begun. The fish will dig a pit and will then spawn. Do not disturb them during spawing. The female will then swim away and the male will guard the nest. The eggs should be raised in a seperate tank and the fry should be given baby brine shrimp once they are free swimming. It should be noted that breeding this fish is difficult and an optimal process for doing so is not well established.
The Red Pirahna is only available in states where they are legal. Prices vary.
Animal-World References
Freshwater Fish and Plants
Tropical Fish ~ Freshwater Fish ~ Aquatic Plants
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