Elysia grandifolia is a species of sea slug, a marine gastropod mollusc in the family Plakobranchidae native to the waters off southern India and Sri Lanka.

Kelaart was a military surgeon who became interested in marine life after seeing an aquarium in London, and set about describing nudibranchs off the waters of Ceylon (Sri Lanka), where he was stationed.

[1][2] Sometimes reaching 12 cm (4.8 in) long,[3] Elysia grandifolia has a light green head and body, marked with white and more rarely black spots.

Running along the length of the body on each side is a veiny green wing-like membrane—known as a parapodium—with black and gold margin.

[3] It is an introduced species in the eastern basin of the Mediterranean Sea, where it has been recorded off the coast of Turkey and Israel.