From WikiPedia: "
The Oriental Darter or Indian Darter (Anhinga melanogaster), sometimes called Snakebird, is a water bird of tropical South Asia and Southeast Asia. It is a cormorant-like species that has a very long neck. It often swims with only the neck above water. It is a fish-eater."
Canon EOS 400D with Canon EF 70-200mm F/4 L IS USM couple with Tamron SP AF 1.4X TC. Photographed at Kumarakom.
Thanks to Vimal for helping me identify this bird.