Which one of the following is the national aquatic animal of India?

Which one of the following is the national aquatic animal of India?

Saltwater crocodile
Olive ridley turtle
Gangetic dolphin
Gharial
This question was previously asked in
UPSC IAS – 2015
The Gangetic dolphin (Platanista gangetica) is the national aquatic animal of India.
The Gangetic dolphin was declared the national aquatic animal by the Indian government on May 18, 2009.
The Gangetic dolphin is a freshwater dolphin species found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of India, Nepal, Bangladesh, and Bhutan. It is an indicator species of the health of the river ecosystem. It is listed as endangered by the IUCN. The other options are also aquatic animals found in India but are not designated as the national aquatic animal.