Home / Fishes / Freshwater stingrays / Ocellate river stingray
Some federal rules applyOcellate river stingray
Potamotrygon motoro
Fishes › Freshwater stingrays (Myliobatiformes) › Potamotrygonidae (Freshwater stingrays)
The ocellate river stingray (Potamotrygon motoro), also known as the peacock-eye stingray or black river stingray, is a species of freshwater stingray in the family Potamotrygonidae.
Care at a glance
Species-specific aquarium care
- Tank: At least 96 in long and 39 in front to back for one adult (adults commonly reach about 19.7 in / 50 cm).
- Water: Freshwater.
- Temperature: 75–79°F (range recorded for this species).
- pH: 5–6.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- 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
- Tank: a base of at least 94 × 35 in (roughly 428 US gallons); space needed is rated “very large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 75–79 °F, pH 6–7.5, 1–12 dGH.
- Difficulty: Difficult (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Strictly speaking, decor isn't really necessary in a tank set up to house rays.”
- Diet: “Wild rays feed chiefly on other fish and aquatic invertebrates, including worms and crustaceans.”
- Tankmates: “Rays are among the top predators in the ecosystems they populate in nature and are unsafe to keep with most other species.”
- Breeding: “Potamotrygon species utilise a breeding strategy known as matrotrophic viviparity.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Freshwater stingrays
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 (often 6×3 ft+ footprint for one adult) with fine sand and excellent filtration.
Diet
- Earthworms, shrimp and fish.
Health watch
- Venomous barb; banned in some states.
Understanding the animal
About this animal
About this animal
It was the first species to be described in the family and is also the most widespread, ranging throughout much of the Río de la Plata, Amazon, Mearim and Orinoco basins in tropical and subtropical South America. It is sometimes kept in aquaria.
Quoted from the Wikipedia article “Ocellate river stingray” (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. Uses both the bottom and open water. Found in freshwater rivers. It is an extremely dangerous species. Maximum length reported in Axelrod et al., 1991. |
| Water it lives in | Freshwater, 75–79 °F (24–26 °C), pH 5–6, hardness 10 dH. |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: internal live bearers. |
What this means for care
- Keep water within its wild range, 75–79 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 90°F (up to 93°F in the hottest sampled areas) |
| Cool-season lows | about 69°F (down to 54°F in the coldest sampled areas) |
| Average temperature | 73–81°F across sampled records |
| Relative humidity | 75–84% on average (driest month about 74%) |
| Rainfall | about 2178 mm a year |
Measured at 233 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 ocellate river stingray (Potamotrygon motoro), also known as the peacock-eye stingray or black river stingray, is a species of freshwater stingray in the family Potamotrygonidae. It was the first species to be described in the family and is also the most widespread, ranging throughout much of the Río de la Plata, Amazon, Mearim and Orinoco basins in tropical and subtropical South America. It is sometimes kept in aquaria. — 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 |
| Behavior | Ocellate river stingrays are potamodromous, migrating within freshwater rivers and streams. — Animal Diversity Web |
| Reproduction | 16 pups were born by one female in captivity. — FishBase |
| Lifespan | Information regarding lifespan in the wild is unavailable. — Animal Diversity Web |
| Appearance and size | These stingrays can be distinguished from closely related species (such as large spot stingrays ( Potamotrygon falkneri )) by the presence of orange to yellow dorsal eyespots, each surrounded by a black ring, with diameters larger than the eyes. — Animal Diversity Web |
| Biology | Found in freshwater rivers. It is an extremely dangerous species. Maximum length reported in Axelrod et al., 1991 is 100 cm TL. — FishBase |
| History and naming | Potamotrygon motoro varies significantly in appearance and morphology over its large range, and a taxonomic review of the Amazonian populations is expected. — 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 disc width. Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 94 × 35 in (about 428 US gallons).
Veterinary & husbandry research
Veterinary & husbandry research
- Ichthyological ethnoknowledge of the "piabeiros" from the Amazon region, Brazil da Silva Ladislau D et al., Journal of ethnobiology and ethnomedicine 2021
- PRESUMPTIVE DYSGERMINOMA IN AN ORANGE-SPOT FRESHWATER STINGRAY (POTAMOTRYGON MOTORO) Jafarey YS et al., Journal of zoo and wildlife medicine: official publication of the American Association of Zoo Veterinarians 2015
- Envenomation by Amazonian freshwater stingray Potamotrygon motoro: 2 cases reported in Europe Brisset IB et al., Toxicon: official journal of the International Society on Toxinology 2006
- Dangerous Measures: A Case Report and Review of Motoro Ray Envenomation Dwek P et al., Toxins 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. See all 5 on PubMed → 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.
- Species+ (UNEP-WCMC and the CITES Secretariat) Zoo, university or veterinaryThe official database of species listed under CITES.
- USFWS International Affairs: CITES Zoo, university or veterinaryFederal agency that issues CITES permits.
- 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.
- Clint's Reptiles (YouTube): Freshwater Stingray, The Best Pet Fish? Expert educator & keeperClint Laidlaw, PhD in Biology Education and MS in Evolutionary Ecology; owner of Clint's Reptile Room and a longtime keeper. His "Best Pet?" series reviews each species' care in depth.
- 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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