Which shark is a true freshwater species found in rivers?

The Ganges shark is the true freshwater shark species found in rivers. Its scientific name is Glyphis gangeticus, and it is associated chiefly with the Ganges–Hooghly and Brahmaputra river systems in India and Bangladesh.

This shark is adapted to muddy, low-visibility river water. Its small eyes, upward-tilted gaze and slender teeth suggest a fish-eating lifestyle in turbid habitats, where smell, hearing and electroreception may be more useful than clear underwater vision. Newborn individuals have also been reported from the Hooghly River, suggesting that freshwater may serve as nursery habitat.

The most important mix-up is the bull shark. Bull sharks can travel far into freshwater and may occur in some of the same rivers, but they are a marine species that tolerates freshwater rather than a true freshwater river shark. “River shark” can also refer more broadly to members of the genus Glyphis.

The Ganges shark is extremely rare and classified as Critically Endangered. Historical records were often confused with bull sharks, making its genuine distribution and population size difficult to establish.