Home / Fishes / Freshwater stingrays / Smooth back river stingray
Some federal rules applySmooth back river stingray
Potamotrygon orbignyi
Fishes › Freshwater stingrays (Myliobatiformes) › Potamotrygonidae (Freshwater stingrays)
Potamotrygon orbignyi, the smooth back river stingray or reticulate freshwater stingray, is a species of river stingray in the family Potamotrygonidae.

Care at a glance
Species-specific aquarium care
- Tank: At least 72 in long and 27 in front to back for one adult (adults commonly reach about 13.8 in / 35 cm).
- Water: Freshwater.
- Temperature: 75–79°F (range recorded for this species).
- pH: 6.8–7.5.
- 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.
- Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.
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, 75–79 °F, pH 6–7.5, 0–10 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 is found in the Amazon and Orinoco River basins in South America.
Quoted from the Wikipedia article “Potamotrygon orbignyi” (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. Occurs in stream swamps, floodplain lakes and artificial lagoons. Feeds mainly on insects and benthic crustaceans. |
| Water it lives in | Freshwater, 75–79 °F (24–26 °C), pH 6.8–7.5. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
What this means for care
- Keep water within its wild range, 75–79 °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 70°F (down to 64°F in the coldest sampled areas) |
| Average temperature | 77–82°F across sampled records |
| Relative humidity | 76–83% on average (driest month about 73%) |
| Rainfall | about 2268 mm a year |
Measured at 216 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 | Potamotrygon orbignyi, the smooth back river stingray or reticulate freshwater stingray, is a species of river stingray in the family Potamotrygonidae. It is found in the Amazon and Orinoco River basins in South America. — 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 |
| Biology | Occurs in stream swamps, floodplain lakes and artificial lagoons. Feeds mainly on insects and benthic crustaceans. — FishBase |
| History and naming | The genus name Potamotrygon comes from the Greek words potamos (river) and trygon (sting ray). The species name is in honor of Alcide Charles Victor Marie Dessalines d'Orbigny. — 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
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.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- 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.
