Ocellate river stingray (Potamotrygon motoro) care guide

Group
Freshwater fish
Other names
Ocellate river stingray, South American freshwater stingray, P01, P03, P044
Family
Potamotrygonidae (river stingrays)
Origin
Widespread in South America: Amazon, Orinoco, Paraná–Paraguay and Uruguay basins in Colombia, Peru, Bolivia, Brazil, Paraguay, Uruguay and Argentina.
Water
freshwater
Maximum size
50 cm
Temperature
24–26°C
pH
6–7.5
Hardness
Soft to medium, 1–12 dGH
Minimum tank
1620 litres
Care level
expert
Temperament
semi_aggressive

Care

Warning: this is a venomous fish. The motoro carries one or more barbed spines on the top of its tail which deliver a protein-based venom causing intense pain and tissue damage. Take great care when working in the tank, never handle the ray with bare hands, and keep children away. Rays shed their spines roughly every six months, and a shed spine is still venomous, so look for it in the sand and remove it carefully. This is a very large fish. Disc width is around 50 cm, with a total length including the tail of up to about a metre. An adult or pair needs a tank of at least 240 × 90 × 75 cm (around 1,620 litres), and it is the floor area that matters. It is only suitable for experienced keepers with the space and budget for a huge aquarium and strong filtration. A very tight-fitting cover is essential, as rays can jump. Soft river sand is the best substrate; avoid sharp gravel, which can damage the underside. Keep open swimming space and very little decor on the floor. Rays are sensitive to poor water quality: they need stable, very clean water with low nitrate, at 24–26 °C (a narrow range), pH 6–7.5 and soft to medium hardness. Heavy feeding means large, frequent water changes. Many become very tame and learn to recognise their keeper. The motoro is variable in pattern and is sold under several 'P numbers' and colour names such as blue, orange, black or marbled; it may be a complex of more than one species. FishBase gives its IUCN status as Least Concern (assessed 2024). Sources: Seriously Fish (seriouslyfish.com/species/potamotrygon-motoro/); FishBase (fishbase.se/summary/Potamotrygon-motoro.html); Wikipedia (en.wikipedia.org/wiki/Potamotrygonmotoro). Checked October 2026.

Diet

A predator of fish and aquatic invertebrates. Feed at least twice a day on varied meaty foods such as mussels, cockles, prawns, squid, whitebait, earthworms and bloodworm. Do not feed beef heart, chicken or other mammal or bird meat, as rays cannot properly digest the fats.

Breeding

Livebearing: the young develop inside the mother, nourished by uterine secretions, and are born fully formed after a gestation of about 9–12 weeks in captivity. It breeds readily in large aquariums. Males can be extremely aggressive towards females during courtship, so watch closely and be ready to separate them.

Compatibility and tank mates

A predator that will eat any fish it can catch, especially bottom-dwellers. Suitable companions are large, peaceful fish that stay in the upper water, such as large cichlids, arowanas, large characins and cyprinids. Avoid any fish small enough to eat.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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