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Pirapitinga

Piaractus brachypomus

Also known as Cachama

Fishes › Tetras, piranhas and pacus (Characiformes) › Serrasalmidae (Piranhas and pacus)

Piaractus brachypomus also known as the red-bellied Pacu or pirapitinga, is a large species of pacu, a close relative of piranhas and silver dollars, in the serrasalmid family.

Aquarium hobby
Experience: Intermediate
Pirapitinga
Photo: w_endo, CC0, via Wikimedia Commons
FamilyPiranhas and pacus
Record lifespan28 years
Adult lengthup to 34.6 in
WaterFreshwater

Care at a glance

Species-specific aquarium care

  • Tank: At least 210 in long and 69 in front to back for one adult (adults commonly reach about 34.6 in / 88 cm).
  • Water: Freshwater.
  • Temperature: 73–82°F (range recorded for this species).
  • pH: 4.8–6.8.
  • Hardness: 0–15 dGH.
  • Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
  • Diet: FishBase classes it as a herbivore.
  • Safety: Can injure people (sharp spines, teeth or electric shock): use nets and care when working in the tank.

Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.

Care guide

Species care notes

  • Tank: a base of at least 118 × 35 in (roughly 642 US gallons); space needed is rated “very large tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 73–82 °F, pH 4.8–7.5, 0–15 dGH.
  • Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “The size of the tank and filtration used are much more important than the choice of decor.”
  • Diet: “Stomach analyses of wild specimens show it to be primarily a herbivorous species, feeding on fruits, nuts and seeds.”
  • Tankmates: “Small fish will likely be eaten but in general it's quite peaceful with bigger species.”
  • Breeding: “Not achieved in the hobby, although it's being bred in some numbers for food in both South America and various Far Eastern countries.”

From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167

Group care guide

Piranhas, pacus and silver dollars

Applies to most species in this group. Habitat: South American rivers. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

  • Large tanks with strong filtration; pacus grow to over 2 ft and outgrow almost every home aquarium.

Sources 117119164118

Diet

  • Silver dollars: plant-based foods. Piranhas: fish, shrimp and pellets.

Sources 117119164118

Health watch

  • Piranhas are banned in many states. Never release pacus.

Sources 117119164118

Understanding the animal

About this animal

About this animal

As with a number of other closely related species, P. brachypomus is often referred to as the red-bellied pacu in reference to the appearance of the juveniles. This has resulted in a great deal of confusion about the nature and needs of all the species involved, with the reputation and requirements of one frequently being wrongly attributed to the others.

Quoted from the Wikipedia article “Piaractus brachypomus” (CC BY-SA 4.0) 174

In the wild

In the wild

From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1

Where it livesLives in freshwater, in rivers and streams. Juveniles mimic Serrasalmus nattereri. Feeds on insects and decaying plants.
Water it lives inFreshwater, 73–82 °F (23–28 °C), pH 4.8–6.8, hardness 15 dH.
ClimateTropical climate.
Wild dietOther.
Behavior to plan forBreeding: brood hiders.

What this means for care

  • Keep water within its wild range, 73–82 °F.
  1. FishBase species summary: Piaractus brachypomus
Native climate (measured)

Native climate (measured)

Warm-season highsabout 90°F (up to 94°F in the hottest sampled areas)
Cool-season lowsabout 69°F (down to 60°F in the coldest sampled areas)
Average temperature75–81°F across sampled records
Relative humidity77–84% on average (driest month about 75%)
Rainfallabout 2217 mm a year

Measured at 207 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

From the sources

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

OverviewPiaractus brachypomus also known as the red-bellied Pacu or pirapitinga, is a large species of pacu, a close relative of piranhas and silver dollars, in the serrasalmid family. As with a number of other closely related species, P. brachypomus is often referred to as the red-bellied pacu in reference to the appearance of the juveniles. This has resulted in a great deal of confusion about the nature and needs of all the species involved, with the reputation and requirements of one frequently being wrongly attributed to the others. — Wikipedia (community-edited)
Where it livesHome ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase
Social life and communicationPacu, like other characins, can be very sensitive to environmental disturbances. — Animal Diversity Web
Wild dietThe dietary composition of red-bellied pacu (and a number of closely related species) shifts depending on the season. — Animal Diversity Web
BehaviorIn native environments, red-bellied pacu are shoaling fish that may become more independent with age. — Animal Diversity Web
ReproductionAssuming standard charicid mode of reproduction. — FishBase
LifespanRed-bellied pacu are long-lived fish, with popular aquarium sites quoting life spans of 25 years and beyond. — Animal Diversity Web
Appearance and sizeMaximum length 88.0 cm tl male/unsexed; maximum published weight 25.0 kg; maximum reported age 28 years. — FishBase
BiologyJuveniles mimic Serrasalmus nattereri. Adults feed on insects and decaying plants. They possess powerful dentition that can cause serious bites. — FishBase

Data and studies

The numbers

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Maximum recorded lifespan

Highest reported28years
AnAge 16228
FishBase 16428

Longest recorded lifespan reported by each database; typical lifespans are usually shorter.

Typical adult weight

Average of sources42.7lb
AnAge 16230.3
FishBase 16455.1

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Adult length

Average of sources34.6in
FishBase 16434.6
Seriously Fish species profiles 16734.6

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Average of sources73–82°F
FishBase 16473–82
Seriously Fish species profiles 16773–82

Range the species tolerates in nature; aim for the middle.

pH

Average of sources4.8–7.2
FishBase 1644.8–6.8
Seriously Fish species profiles 1674.8–7.5

Water hardness

Reported0–15dGH
Seriously Fish species profiles 1670–15

Minimum tank footprint

Reported118in
Seriously Fish species profiles 167118

Seriously Fish recommends a tank base of at least 118 × 35 in (about 642 US gallons).

Veterinary & husbandry research

Veterinary & husbandry research

Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. See all 24 on PubMed → 170

Sources for this sheet

  1. AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) Peer-reviewed researchCurated, referenced longevity and life-history records for thousands of species; maximum lifespans are often from zoo animals.
  2. FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
  3. Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
  4. Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  5. Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  6. Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  7. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
  8. PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
  9. iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.