Fish, Tanks and Ponds


Fish, Tanks and Ponds
A comprehensive guide to fish

Potamotrygon orbignyi

Reticulated stingray

Kissing gourami, Helostoma temminckiiKissing gourami, Helostoma temminckii
Photos by Andy Rapson

Etymology:

Potamotrygon: Greek, potamos = river + Greek, trygon = a sting ray

General Notes:

A widespread species that may require subdivision. Rosa recognizes Potamotrygon dumerilli (Castelnau 1855) and Potamotrygon humerosus Garman 1913 as distinct species, but evidence given is meager.
Stingrays are delicate fish and if kept in poor conditions they become vulnerable to bacterial and other infections. They require a large floor area rather than depth due to their shape and habit. Stingrays are highly predatory so tank mates should be to large to be eaten but calm and peaceful so as not to intimidate the stingrays. Ideally the tank mates should occupy the higher reaches of the aquarium so that there will be little interaction between them and the stingrays. Stingrays are called this for a reason, they possess a barb on their tail which is venomous and quite dangerous, they will use it in self defence so they must never be cornered or threatened and caution must be used at all times when handling them.

Feeding

Wild stingrays are predatory and prey on fishes, insects and crustaceans. Their captive diet must reflect this since dried food is unlikely to be accepted. They will eat dead food without any problem and so frozen lancefish, whitebait, sardines ect can all be used.

Sexing

The sexes are easily told apart because this is a live bearing species and males have claspers which are male sexual organs on each side of their pelvic fins, females don't have these.

Breeding

Breeding these fish is difficult, they are live bearers and don't have a breeding season. Females give birth to one to eight young which are known as pups. Captive breeding is down to keeping a pair in top condition and luck. Unusually for fish, the fry develop inside the female and instead of relying on a large yolk sac the fry actually take nourishment directly from their mother. The pups are born fully formed and fully independant.

Wild status

Potamotrygon orbignyi is a widely distributed freshwater stingray found throughout numerous river systems of the Amazon Basin. It does exhibit geographical variation. The species is taken as food and juveniles are taken for the ornamental fish market. In some areas, its habitat is threatened by illegal mining activities. It is also persecuted in tourist areas and also targeted in sports fisheries. It is assessed as Least Concern due to its wide distribution and abundance by the ICUN Red list of Threatened Species.

Information at a glance

pH: 6.8 - 7.5
dGH: 4 - 12
Temperature: 24 - 26°C (75 - 78°F)
Lighting:
Diet: Carnivore
Size:35cm (14in) (Diameter).
Min tank size: 675 litres
Difficulty level: Very difficult
Aquarium type: Species/Community
Swimming level: Bottom

Distribution and habitat

distribution map for Helostoma temminckii

Origin: South America: Widespread in Amazon and Orinoco River basins and in river systems in Suriname, Guyana and French Guiana.

Habitat: Rivers, stream swamps, floodplain lakes and  lagoons.

Classification

Kingdom: Animalia
Phylum: Chordata
Class: Elasmobranchii
Order: Rajiformes
Family: Potamotrygonidae
Genus: Potamotrygon
Species: P. orbignyi (Castelnau, 1855)

Common name:
Reticulated stingray, Teacup Stingray, Smoothback stingray

Synonyms: Potamotrygon reticulatus, Trygon reticulatus, Potamotrygon dumerilii, Trygon dumerilii, Trygon orbignyi