The Ganges and Brahmaputra river systems are one of the richest turtle habitats in the country country. Out of the 24 recognized species, these rivers inhabit 19 of them, most of which are not found anywhere else. These include some of the rarest softshell species too.
In the Brahmaputra mainstem, more than 17000 individuals were encountered during a single survey in 2018. These were water birds of 46 species with three Endangered, two Vulnerable and 4 Neat Threatened according to the IUCN. The sand banks of the Chambal rivers are also nesting grounds for the the Indian Skimmer. The Brahmaputra water also are a source for multiple wetlands such as the Maguri in Assam etc., that support a whole range of birds.
The small-clawed otter and the smooth-coated otters are diurnal animals that largely inhabit regions with minimum human presence. While both these species are considered vulnerable, the sand banks of much of the Brahmaputra banks are marked with their tracks and spraints of at least one of them, in good numbers.
Dolphin habitats are also home to multiple other species. The Hilsa fish, Tenualosa ilisha, is an anadromous fish that has large-scale upstream migration from oceans and spawn in the Ganges river systems. The Sperata aor is a commercially important fish and is also a potential feed of these dolphins. Eutropiichthys vacha is Endangered in India and Critically Endangered in Bangladesh, a catfish species, inhabits these freshwater. Similarly, Setipinnia phasa, a potamodromous fish found in the waters of Bengal and Orissa is known for its environmentally induced reproductive plasticity.