Home / Fishes / Tetras, piranhas and pacus / Redeye piranha
No federal permit to keepRedeye piranha
Serrasalmus rhombeus
Fishes › Tetras, piranhas and pacus (Characiformes) › Serrasalmidae (Piranhas and pacus)
The redeye piranha (Serrasalmus rhombeus), also known as the black piranha, white piranha, spotted piranha or yellow piranha, is a species of freshwater ray-finned fish belonging to the family Serrasalmidae, which includes the pacus, piranhas and…
Care at a glance
Species-specific values
Values researched for this exact species. Where they differ from the group guide below, follow these. Air, surface and water temperatures are listed separately, and each source is kept as published rather than averaged.
| Water temperature | 72–82 °F (22.2–27.8 °C) Seriously Fish aquarium recommendation; not a wild collection measurement. | 283 |
| Water pH | 4.5–7.5 pH Seriously Fish aquarium recommendation; not a wild collection measurement. | 283 |
| Water general hardness | 1–20 dGH Seriously Fish aquarium recommendation; not a wild collection measurement. | 283 |
| Maximum standard length | 450 mm SL Source maximum; not total length or a guaranteed adult size. | 283 |
| Minimum tank dimensions | length: 210 cm; width: 45 cm; height: 45 cm One fully grown adult; source taxonomic/stock identification uncertainty applies. | 283 |
| Social needs | Maintain singly; conspecific fighting makes a routine group setup unsuitable. | 283 |
Species-specific aquarium care
- Tank: At least 84 in long and 33 in front to back for one adult (adults commonly reach about 16.3 in / 41.5 cm).
- Water: Freshwater.
- Temperature: 73–81°F (range recorded for this species).
- pH: 5.8–7.
- Hardness: 0–10 dGH.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
- 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 83 × 18 in (roughly 112 US gallons); space needed is rated “very large tank”.
- Water: 72–82 °F, 1–20 dGH.
- Behaviour: temperament species tank; kept alone.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Requires a well-oxygenated set-up, ideally furnished with a sandy substrate and some driftwood roots and branches to provide cover.”
- Diet: “Wild fish are opportunistic, feeding on the fins and flesh of other species as well as smaller fishes, insects and crustaceans.”
- Tankmates: “Should only be considered as a specimen fish for the enthusiast since it doesn't make a good tankmate for anything else.”
- Breeding: “This species has only rarely been bred in captivity with the main restriction appearing to be the volume of water required to avoid the fish murdering one another.”
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
It is found in northern South America. It is the type species of the genus Serrasalmus.
Quoted from the Wikipedia article “Redeye piranha” (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, in rivers and streams, lakes. Uses both the bottom and open water. Occurs in the rapids but is also captured in deep zones of main rivers with the use of fish bait. Is essentially a carnivore, feeds on small fish, crabs, mammals, lizards and coleopteran insects. Its opportunistic behavior allows it to adapt to various biotopes. |
| Water it lives in | Freshwater, 73–81 °F (23–27 °C), pH 5.8–7, hardness 10 dH. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
What this means for care
- Keep water within its wild range, 73–81 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 91°F (up to 95°F in the hottest sampled areas) |
| Cool-season lows | about 69°F (down to 62°F in the coldest sampled areas) |
| Average temperature | 77–81°F across sampled records |
| Relative humidity | 76–83% on average (driest month about 73%) |
| Rainfall | about 2175 mm a year |
Measured at 826 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 | The redeye piranha (Serrasalmus rhombeus), also known as the black piranha, white piranha, spotted piranha or yellow piranha, is a species of freshwater ray-finned fish belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. It is found in northern South America. It is the type species of the genus Serrasalmus. — 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 |
| Appearance and size | The redeye piranha is the largest species of piranha. It has a distinctively rhombus-shaped body, solidly coloured from grey through to nearly black. Whatever the body colour, this species has red eyes. — Wikipedia (community-edited) |
| Biology | Adults occur in the rapids but is also captured in deep zones of main rivers with the use of fish bait. They are essentially carnivores feeding on small fish, crabs, mammals, lizards and coleopteran insects. Their opportunistic behavior allow them to adapt to various biotopes. — FishBase |
| History and naming | The redeye piranha was first formally described in 1766 as Salmo rhombeus, with the type locality given as Brokopondo on the Suriname River in Surinam. When Bernard Germain de Lacépède created the genus Serrasalmus in 1803, the only species he placed in it was Salmo rhombeus, so this species is the type species of its genus. — 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 in nature; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 83 × 18 in (about 112 US gallons).
Veterinary & husbandry research
Veterinary & husbandry research
- New insights into patterns and rates of tooth replacement in serrasalmid and characid fishes, with implications for the subsistence fishery of Peru's remote ribereños villages Stuart CE et al., Journal of fish biology 2021
- Effects of water pH and calcium concentration on ion balance in fish of the Rio Negro, Amazon Gonzalez RJ et al., Physiological zoology 1998
- Mercury contamination and human exposure through inland fishery and aquaculture products in Northeastern Brazil de Lacerda LD et al., Environmental monitoring and assessment 2026
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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