Fish, Tanks and Ponds


Fish, Tanks and Ponds
A comprehensive guide to fish

Potamotrygon motoro

Ocellate River Stingray

Ocellate River Stingray, Potamotrygon motoroOcellate River Stingray, Potamotrygon motoro
Photos by Andy Rapson

Ocellate River Stingray, Potamotrygon motoro

Don't under estimate the size of these fish when adult. This specimen was in a 500gall (2250 litres) tank measuring L, W, H - 240cm x 120cm x 75cm (8ft x 4ft x 2.5ft) and the tank is barely big enough.

Etymology:

Potamotrygon:
Greek, potamos = river.
Greek, trygon: = sting ray.

General Notes:

Excellent filtration and maintenance regime is mandatory when keeping stingrays. Stingrays are Elasmobranchs and they have a skeleton of cartlidge rather than bone, they lack swim bladders. Some Elasmobranchs appear very similar to bony fish but they have very different physiologies. One difference which is very important to fish keepers is that they don't tolerate medication at all well.
Stingrays which are given less than perfect care can and do fall victim to various bacterial infections and these often prove fatal due to the difficulties in treating them.
Their aquarium should have a large floor space with depth being less important and with a sandy substrate. Don't use to much decor which could makes it difficult for stingray to negotiate its way around, instead keep things very simple. Above all be realistic when you are tempted to purchase a 30cm (12in) baby for your 6ft tank. If you can't house the adult then don't make the purchase.

Feeding

Potamotrygon motoro is a carnivore, their natural diet includes - insects, molluscs, crustaceans, annelids (worms) and fish. In captivity they require pretty much the same. Live prey is not necessary as the frozen alternatives are all readily accepted with the advantage of being less risky from a health point of view.

Compatibility

Peaceful with fish which are to large to eat. Stingrays are easily bullied and damaged. If their disc is damaged there is a possibility of infection and this may prove difficult to treat and may even prove to be fatal. It is essential that stingrays are kept either in a species tank or with other largish but peaceful species.
Surface living fish such as Arowana make good tank mates because the two species inhabit different niches and rarely come in to contact.

Sexing

Male stingrays have "claspers" which are used for internal fertilisation. They are paired and are located on each side of the pelvic fins. The claspers are clearly visible even in very young fish.
Apart from keeping pairs with very similar patterns together and offering the very best of care there is little more the amateur aquarist can do in order to encourage breeding.

Breeding

Potamotrygon motoro is a live bearing fish which gives birth to 3 - 20+ live babies which measure around 30cm in diameter at birth, after a gestation period of around three months.

Wild status

IUCN Redlist - Data deficient. Possible threats include, over collection for the aquatic trade, over fishing (Stingrays are apparently very good to eat), hydro-electric plants, habitat loss.

Additional information

Information at a glance

pH: 5 - 6
dGH: 2 - 8
Temperature: 22 - 26°C (72 - 78°F)
Lighting:
Diet: Carnivore
Size: 90cm (36in), usually less.
Min tank size: 2,000 litres
Difficulty level: Very difficult.
Aquarium type: Species/Community
Swimming level: Bottom

Distribution and habitat

distribution map for Ocellate River Stingray, Potamotrygon motoro

Origin: S America, Amazon and Orinoco river basins.

Habitat: Lakes, rivers and streams where there is a sandy or muddy substrate.

Classification

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Myliobatiformes
Family: Potamotrygonidae
Genus: Potamotrygon
Species: P. motoro, (Müller & Henle, 1841)

Other common names:
Motoro Stingray

Synonyms:
Potamotrygon pauckei,
Taeniura motoro