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Pygocentrus nattereri

Red Bellied Piranha

Classification

Characidae. Subfamily: Serrasalminae

Distribution

This species is very widespread in nature, having been recorded from Venezuela, Colombia, Ecuador, Guyana, Brazil, Peru, Bolivia, Paraguay, Argentina and Uruguay. It occurs in the drainages of several major rivers including the Amazon, Rio Paraguay, Rio Paraná and Rio Essequibo, as well as numerous smaller systems.

Habitat

Inhabits rivers, tributaries, creeks, areas of flooded forest, lakes and pools. It’s particularly common in the famous Pantanal wetlands of southwestern Brazil.

Maximum Standard Length

12″ (30cm)

Aquarium SizeTop ↑

48″ x 18″ x 15″ (120cm x 45cm x 37.5cm) – 200 litres. Suitable for a shoal of subadult fish.

Maintenance

Sandy substrate, plants and bogwood to form areas of cover, plenty swimming space. Lighting should be dimmed.

Water Conditions

Temperature: 24 – 26°C (75 – 79°F)

pH: 6 – 7

Hardness: Up to 18 °gH but prefers softer water

Diet

An opportunistic and omnivorous feeder. Gut analyses of wild fish have shown it to consume not only other fish, but also crustaceans, insects, plant matter and even small reptiles. Meaty foods such as prawn, whitebait, mussels, lancefish etc, thought to be omnivorous in the wild but rarely accepts non meaty foods in captivity.

Behaviour and CompatibilityTop ↑

Can be kept with other red bellies and other fish from the pygocentrus genus, subject to a large enough aquarium being provided. There is always an element of risk to this as, even in an established group, there is still the potential for aggression. If a fish were to be injured, it could then become a target and be eaten by the other fish.

Sexual Dimorphism

Not sexually dimorphic

Reproduction

Difficult but red bellies have been bred in home aquaria. A large tank of 72″x24″x24″ is needed and it is best to have shoal of approximately six fish from which a pair will hopefully form The fish go very dark when inbreeding condition. The pair will split off from the group and excavate a pit in which spawning occurs.

Hundreds of fry are produced in each spawning and can be fed on newly hatched brineshrimp once they are free-swimming. Fry are cannibalistic and the larger fry will inevitably eat the smaller ones. Unless there is sufficient space to house all the fry, this is an effective way of controlling the size of the brood and ensuring only strong fish survive.

NotesTop ↑

Many people who keep red bellies are disappointed to find that they do not live up to their reputation as vicious man-eaters. In fact, red bellies are a fairly timid fish and will spend much of their time lurking under cover. As mentioned, they prefer an aquarium with hiding places and low lighting levels. If this is provided, then the fish are likely to be more active as they will feel more secure in their surroundings. Keeping them in a shoal of at least four fish will also help overcome their timidity.

While it is true that red bellies are wary of humans, the same is not true of potential tankmates. Some piranha owners successfully keep fish such as plecostomus catfish or even small tetras, like neons, with their red bellies. This is not recommended and in most cases, the tankmates will be eaten, even if they have lived together happily for a lengthy period of time.

Red bellies are not fussy eaters and will readily accept the foods listed above and more. Non-fish based foods like chicken and other meat can be fed but in strict moderation, as they are not really the ideal diet for piranhas. Bear in mind that all these foods are highly polluting and any uneaten food should be removed as soon as possible. It is not necessary, or desirable, to feed live fish to piranhas. Many owners turn to live fish if their piranha refuses to eat dead food but with perseverance, all red bellies can be weaned off live fish. Dead food should be offered on a daily basis and removed if not eaten. Eventually, the fish’s survival instinct will kick in and it will begin to accept the dead food. Increasing the temperature and boosting the water flow in the tank can also help encourage a stubborn fish to eat as it boosts the metabolism.

There is also a yellow bellied variant of p. nattereri which is sometimes (incorrectly) called pygocentrus ternetzi but it is not distinct species. Similarly there is speculation that the fish we believe to be p. nattereri may in fact be pygocentrus altus but further study is needed.

There are currently only three scientifically recognised pygocentrus species; nattereri, caribe and piraya.