Home / Fishes / Tetras, piranhas and pacus / San Francisco piranha
No federal permit to keepSan Francisco piranha
Pygocentrus piraya
Fishes › Tetras, piranhas and pacus (Characiformes) › Serrasalmidae (Piranhas and pacus)
Pygocentrus piraya, often called the piraya piranha or San Francisco piranha, and sometimes sold as the man-eating piranha, is a species of freshwater ray-finned fish belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes.
Care at a glance
Species-specific aquarium care
- Tank: At least 90 in long and 30 in front to back for one adult (adults commonly reach about 15.0 in / 38 cm).
- Water: Freshwater.
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
- Safety: Can injure people (sharp spines, teeth or electric shock): use nets and care when working in the tank.
- Availability: Mostly kept by public aquariums; private keeping is uncommon.
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
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–82 °F, pH 6–8, 2–20 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Some aquarists maintain this species in bare-bottomed arrangements for ease of maintenance, but standard aquarium gravel or sand are both suitable substrates.”
- Tankmates: “Best-maintained alone, although adults may leave much smaller fishes alone if well-fed.”
- Breeding: “Unrecorded, but probably employs a similar reproductive strategy to that of the congener P.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
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.
Diet
- Silver dollars: plant-based foods. Piranhas: fish, shrimp and pellets.
Health watch
- Piranhas are banned in many states. Never release pacus.
Understanding the animal
About this animal
About this animal
This fish is found in the São Francisco River basin in Brazil.
Quoted from the Wikipedia article “Pygocentrus piraya” (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 lives | Lives in freshwater. Dangerous, import prohibited in some countries. Largest of the piranhas. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 92°F in the hottest sampled areas) |
| Cool-season lows | about 58°F (down to 50°F in the coldest sampled areas) |
| Average temperature | 70–78°F across sampled records |
| Relative humidity | 68–77% on average (driest month about 63%) |
| Rainfall | about 1137 mm a year, with strong wet and dry seasons |
Measured at 69 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.
| Overview | Pygocentrus piraya, often called the piraya piranha or San Francisco piranha, and sometimes sold as the man-eating piranha, is a species of freshwater ray-finned fish belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. This fish is found in the São Francisco River basin in Brazil. — Wikipedia (community-edited) |
| Where it lives | Home 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 |
| Wild diet | This fish is an omnivore, and has aggressive tendencies when hungry, stressed, or seeking live food. Like most in the Serrasalmidae family, piraya piranhas dental morphology has a major influence for their inclination toward piscivorous and herbivorous behavior. Members of this genus bear one row of sharp, triangular teeth with a strong lower jaw, which enable them to slice and mince prey with ease. — Wikipedia (community-edited) |
| Appearance and size | It is one of the largest piranhas, reaching a maximum length of 50 cm in the wild, and is sometimes considered the most beautiful, with its orange to yellow belly coloration, silver eyes, and rayed fibrous adipose fin. Like most other piranhas, P. piraya is laterally compressed and roughly circular in profile, and bears a mouthful of very sharp teeth. The lower jaw is thick, strong, and protruding. — Wikipedia (community-edited) |
| Biology | Dangerous, import prohibited in some countries. — FishBase |
| History and naming | The piraya is sometimes available as an aquarium fish. It is not generally bred in captivity, so aquarium pirayas are usually imported from South America and can be expensive. Any other fish sharing a tank with a piraya should be of the same or a similar piranha species. — Wikipedia (community-edited) |
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.
Typical adult weight
Average adult body mass in each database (FishBase gives the maximum recorded weight).
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates; aim for the middle.
pH
Water hardness
Veterinary & husbandry research
Veterinary & husbandry research
- Behavior of Rio Sao Francisco Piranhas in Response to Changes in Space and Density Oldfield RG et al., Zoo biology 2025
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. 170
Sources for this sheet
- 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.
- 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.
- Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- 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.
- Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
- 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.
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