The Red Piranha is a long-time aquarium favorite, but some states do have restrictions on keeping them!
The Red-bellied Piranha Pygocentrus nattereri has a long history with aquarium keepers. It has been kept by aquarists for well over 60 years. This species is also one of the most commonly found piranhas, with a wide distribution throughout the Amazon and Orinoco Basins in South America. Members of the Pygocentrus genus are considered “true piranhas,” and the Red-bellied Piranha is perhaps the most handsome of the group.
The adult Red-belly Piranha has gorgeous coloring. Its back is a steel gray, and the rest of the body is a silvery gold with a bright orangish-red to red throat, belly, and anal fin. This large piranha reaches up to 13 inches (33 cm) in nature, though it is smaller in the aquarium. In the wild, they are found in groups of 20 or so fish. These shoals provide a pack for hunting as well as individual protection from predators. This piranha is considered one of the most ferocious of the piranha predators.
Though Red-bellied Piranhas are not picky eaters and are quite hardy, they are best kept by experienced fish keepers. Red-bellied Piranhas are fascinating and beautiful fish, but you can’t hold or pet them. They are not affectionate, and owners must be extremely careful when handling them. These fish have sharp teeth and an aggressive/defensive nature. Most Piranha bites are sustained when the fish are being handled, though that’s not to say a hungry fish is never dangerous.
Red-bellied Piranhas are highly predacious and not candidates for a community tank. They can be kept singly but are actually one of the easier piranha species to keep in a group. They can be combined with other Pygocentrus species as well as other Red Piranhas. In a group, some of their natural behaviors will show if they are kept under proper conditions. However, even in an established group, aggression and cannibalism amongst piranhas is not unusual. Generally, the largest, most aggressive fish will be dominant. It will demand the best spots in the tank and be the first to feed. Any perceived competition by another fish will be quickly corrected with aggressive behavior of chasing and even inflicting wounds.
A single fish requires a minimum tank size of 40 gallons, but a group requires a much larger aquarium. These big, messy feeders need ample filtration and regular water changes to handle the bio load their feeding puts on the tank. They are generally less skittish and shy when they live in a tank with plenty of hiding places and dimmed lights. Keeping them in a school of 4 or more will also help overcome their timidity.
For more Information and Facts about Piranhas, see:
Piranha: Story of the Piranha Fish from Predator to Prey
- Aquarist Experience Level: Advanced
- Size of fish – inches: 13.0 inches (33.02 cm)
- Minimum Tank Size: 40 gal (151 L)
- Temperament: Aggressive
- Aquarium Hardiness: Moderately Difficult
- Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
- My Aquarium – Enter your aquarium to see if this fish is compatible!
Habitat: Distribution / Background
The Red-bellied Piranha Pygocentrus nattereri (previously Serrasalmus nattereri and Rooseveltiella nattereri) was described by Kner in1858. There is much discussion and debate on the true taxonomy of this fish, so its scientific name may change in the future, but currently it is considered P. nattereri. The species is not listed on the IUCN Red List. Other common names this species is known by are Red Belly Piranha, Red Piranha, and Natterer’s Piranha. A few variants in color have also led to the occasional use of such names as Ternetzi Piranha, Super Red Piranha, Snakeskin Piranha, and Gold-dust Piranha.
Red-belly Piranha are found across a wide geographical range in South America, including Venezuela, Brazil, Peru, Guyana, Bolivia, Paraguay, Argentina, Colombia, Ecuador, and Uruguay. They live in the Amazon River Basin as well as in the basins of the Paraguay, Paraná, and Essequibo Rivers. They also inhabit the coastal rivers of northeastern Brazil and numerous other small water systems.
They inhabit all sizes of running waters, from rivers, to tributaries and creeks. They also are found in larger bodies of water including lakes, pools, flooded forests, and the Pantanal wetlands of southwestern Brazil. These schooling piranha are generally found in groups of 20 to 30 fish.
The Red-bellied Piranha is an opportunistic omnivore with a widely varied diet that includes fish, both whole and in pieces, fish fins and scales, insects, snails, and plants. Though they are scavengers, they are also full-blown predators and will actively give chase to their prey.
- Scientific Name: Pygocentrus nattereri
- Social Grouping: Groups – They are generally found in schools of 20 to 30 fish.
- IUCN Red List: NE – Not Evaluated or not listed
The Red-bellied Piranha can get up to 13 inches (33 cm) in length in the wild, though in captivity they are generally smaller. A lifespan of 10 years is normal, but a few have lived for over 20 years.
These fish have powerful bodies that are high, thick, and laterally compressed. Like all piranhas, they have a keel-like edge that runs along the upper body from head to dorsal fin and along the belly on the lower body. Members of the genus Pygocentrus are all recognizable by the convex shape of their head and massive, bulldog-like lower jaw. With a large, powerful tail and a streamlined body covered with tiny scales, they are very fast and agile swimmers. They also have a small adipose fin between the tail and dorsal fin, a characteristic of all Characins.
Red-bellied Piranha Photo © Animal-World: Courtesy Jonas Hansel
The Red Belly Piranha is gorgeous in its adult coloring. Body colors can be variable, but mostly the back is a steel gray and the rest of the body is a silvery gold with a bright orangish-red or red colored throat, belly and anal fin. It has large black spots on the sides, though they often fade with age, and it sparkles with many shiny scales. In its juvenile form it is more silver colored with dark spots.
The adult Red-bellied Piranha has gorgeous coloring. Colors can be variable, but usually the back is a steel gray and the rest of the body is a silvery-gold with a bright orangish-red or red throat, belly, and anal fin. It has large black spots on its sides, though they often fade with age, and it sparkles with many shiny scales. In its juvenile form it is more silver colored with dark spots.
Some individuals have such intense gold-speckling that they are sometimes called Gold-dust Piranha. There are also two similar species sometimes available in the aquarium hobby. These include the San Francisco Piranha Pygocentrus piraya, which is a yellow-bellied species. Another is the Black Spot Piranha Pygocentrus cariba, which still has the red on its throat and belly, but has a silvery colored body accented with a strong black spot just behind the gill.
- Size of fish – inches: 13.0 inches (33.02 cm) – These fish get up 13 inches (33 cm) in the wild but are usually smaller in captivity.
- Lifespan: 20 years – They generally have a lifespan of about 10 years in captivity though they have been known to live for over 20 years.
Fish Keeping Difficulty
Though Red-belly Piranhas are not picky eaters and are quite hardy, these predacious fish are best kept by experienced fish keepers. You can’t hold or pet them, and they are not affectionate. Owners must be extremely careful, especially when handling them.
- 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 – Owners must be extremely careful, especially when handling them.
Foods and Feeding
Red-bellied Piranhas are carnivorous omnivores. In the wild, their diet is variable, including fish, both whole and in pieces, fish fins and scales, insects, snails, and plants. In captivity, they can be trained to eat whole dead fish, such as frozen silversides and lancefish, as well as a variety of other meaty foods such as prawn, mussels, and fish flesh. They will eat live foods such as feeder fish, earthworms, and river shrimps, but this is not really desirable as it puts a huge pollution load on the aquarium.
- Diet Type: Omnivore
- Flake Food: No
- Tablet / Pellet: No
- Live foods (fishes, shrimps, worms): Some of Diet – These types of foods are not desirable as they can quickly foul the water and place a large bio load on the aquarium.
- Vegetable Food: Some of Diet
- Meaty Food: Most of Diet
- Feeding Frequency: Daily
Red-bellied Piranhas are big, messy feeders, so they need ample filtration and regular water changes to handle the bio load. Water changes of 30 to 50% every other week are recommended.
- Water Changes: Bi-weekly – Do a 30 to 50% water change every other week.
Red-belly Piranha will swim in all parts of the aquarium. A single specimen requires an aquarium of at least 40 gallons, but a group will require a much bigger tank. These apprehensive fish will be less timid if kept in a school of 4 or more. Because they are very messy feeders, they need strong filtration and a moderate water flow to keep up with the bio load.
These rather timid fish will be less skittish and shy in an aquarium with a lot of hiding places. However, they also need plenty of swimming space. This omnivorous species has been reported to eat some aquarium plants. Adding bog wood and placing plants around the perimeter will offer some cover to help them feel at home while leaving an open area for swimming. Provide a substrate of sand or fine gravel, and use dim lighting.
- Minimum Tank Size: 40 gal (151 L) – A 40-gallon aquarium is fine for a single fish, but a group will need an aquarium of 100 gallons or more.
- Suitable for Nano Tank: No
- Substrate Type: Small Gravel
- Lighting Needs: Low – subdued lighting
- Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
- Range ph: 6.5-7.5
- Hardness Range: 4 – 18 dGH
- Brackish: No
- Water Movement: Moderate
- Water Region: All – These fish will swim in all parts of the tank.
This fish sometimes appears surprisingly skittish in the home aquarium. In the wild, the Red-bellied Piranha swims in schools of 20 to 30 fish. These ferocious predators are definitely not candidates for a community aquarium. They can be kept singly but are actually one of the easier piranha species to keep in a group. They can be combined with other Pygocentrus species as well as other Red Piranhas.
A group should contain at least 4 fish. Be warned that even in an established group, aggression and cannibalism are not unusual. A school of piranha is incredibly hierarchal and there will be a clear chain of command. Generally, the largest and most aggressive fish will become dominant. This fish will claim the best spots in the tank and be the first to feed. A challenge by another fish will result in aggressive behavior such as chasing and even inflicting wounds.
- Venomous: No
- Temperament: Aggressive – Although sturdy tankmates may survive alongside this species, it is probably best to keep them in a single species tank.
- Compatible with:
- Same species – conspecifics: Yes – This fish can be kept as a single specimen or in a group of at least 4 or more of its own kind or other Pygocentrus species.
- Peaceful fish (): Threat
- Semi-Aggressive (): Threat
- Aggressive (): Threat
- Large Semi-Aggressive (): Threat
- Large Aggressive, Predatory (): Threat
- Shrimps, Crabs, Snails: Threat – is aggressive
- Plants: Monitor – They have been reported to eat some aquarium plants.
Sex: Sexual differences
This species is not sexually dimorphic. Visual differences between the sexes may possibly be determined if the fish are observed over a long period of time, including pre-spawning activity. However, any color variation is limited to the female being full of roe and the male being in pre-spawning colors. At this time, the male will be more silvery-gold while the female will have more yellow.
Breeding / Reproduction
The Red-bellied Piranha has been bred in home aquariums. Breeding this fish is difficult, however, and no optimal process for doing so has been established. Because this is a very complex species, results can have many variations of spotting, body shape, and coloration.
To attempt breeding, use a very large aquarium that is at least 6 feet in length and 24 inches wide. The first challenge is finding a suitable breeding pair. Sexing is unreliable, although the thickness of the fish has been suggested to indicate gender. A school of at least 6 fish will be needed to have a pair form.
In the wild, spawning usually takes place in the wet season during the months of April and May. Frequent, large water changes should induce breeding as these fish will believe the rainy season has begun. A pair will darken in color, separate from the group, and dig a bowl-shaped spawning pit. The pit will be about 1 1/2 to 2 inches (4 – 5 cm) deep and about 6 inches (15 cm) across.
Do not disturb them during spawning. Spawning takes place with a courtship ritual of swimming in circles and then a ventral-to-ventral interaction. This will induce the female to lay the eggs in the sediment of the pit where they are fertilized. The female will then swim away, and the male will guard the nest. In the wild, the eggs are in clusters and attach to the bottom vegetation.
The eggs should be raised in a separate tank. Each spawn can produce hundreds of fry. Once the fry are free-swimming, they can be fed newly hatched brine shrimp. In nature, they feed on macroscopic plant life. The fry are cannibalistic, so the larger fry will eat smaller siblings. For a general description of characin fish breeding, see Breeding Freshwater Fish: Characins.
- Ease of Breeding: Difficult
Red-bellied Piranha are hardy and disease is not usually a problem in a well-maintained aquarium. That said, there is no guarantee that you won’t have to deal with health problems or disease. Anything you add to your tank can introduce disease. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so as not to upset the balance. Diseases can be passed along from feeding them live foods, so make sure to quarantine live food before feeding. These fish are also at risk for getting wounds inflicted by tankmates. These can lead to contracting bacterial and other infections.
A good thing about Red Belly Piranha is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if dealt with at an early stage. The best way to proactively prevent disease is to give your fish the proper environment and a well-balanced diet. The more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happier. A stressed fish is more likely to acquire disease.
As with most fish, Red Piranhas are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. They are additionally prone to wounds from attacks by tankmates, which can then lead to bacterial or fungal infections. Aquarists should read up on common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Red-bellied Piranha is the most common piranha found for sale in the U.S. However, these fish have provoked fear in conservationists and the media after being irresponsibly released into waterways. Consequently, though they are readily available for sale, they are no longer legal to keep in all states. Before purchasing these fish, be sure to check with the authorities in your area.
- Animal-World References: Freshwater Fish and Plants
- Pygocentrus nattereri (Kner, 1858) Red piranha, Fishbase.org
- Dr. Rüdiger Riehl and Hans A. Baensch, Aquarium Atlas Vol. 1, Publisher Hans A. Baensch, 1991
- Glen S. Axelrod, Brian M. Scott, Neal Pronek, Encyclopedia Of Exotic Tropical Fishes For Freshwater Aquariums, TFH Publications, 2005
- Joseph S. Nelson, Fishes of the World, Wiley, 2006.
- Dr. Herbert R. Axelrod, Aquarium Fishes of the World, TFH Publications, 1998
- Frank Magallanes, True Piranha, Common name: Red Piranha, Natterer’s piranha, red-belly, ternetzi, super red, snakeskin, Pygocentrus nattereri, OPEFE Archives, © http://www.opefe.com/
- Jonas Hansel, Piranha-Info.com, Piranha-Info.com, 2007
- Pygocentrus nattereri Red Bellied Piranha, Seriously Fish, 2012