Ocellate River Stingray
Physical Description: Potomotrygon motoro is a moderate-large ray that can grow beyond 3 feet long (with a disk diameter of approximately 2’) and a weight in excess of 30 lbs. They reach sexual maturity at approximately 10”. Males have distinct modified pelvic fins making is easy to differentiate the sexes. The topside is gray to brown with “peacock-eye” style rings that can range from orange to tan on the disk and a mottled tail.
Range: The most populous of the freshwater stingrays, the ocellated stingray is found in most of the large river basins of southern South America. It prefers quiet waters with sandy or gravel bottoms.
Care considerations: This, like all bladderless fish, is an extremely active swimmer. You’ll need a tank larger in every dimension than the length of the ray so that it can comfortably turn. This stingray is quite sensitive to water quality (particularly ammonia, nitrate, and nitrite levels) and must have a stable PH near 6.0. Regular and frequent water changes are required. Extreme caution should be used when working in the tank, the sting from the barbs are extremely painful and probably will require a hospital visit. The river stingray is a predator and will eat smaller fish, and even attempt larger prey. Shrimp and crustaceans are staple foods, but they will eat a wide variety of other foods including small fish, beef heart, worms, krill and clams. They do best in a species-specific tank, but larger surface-feeding predators can coexist. It is possible to breed this fish, but the live-born fry are even more sensitive to water conditions. .