Asian clam

noun

Definition of Asian clam

: a small, freshwater, bivalve mollusk (Corbicula fluminea) that has a yellowish to brown shell with concentric rows of raised ridges and is chiefly of Asian origin and has been widely introduced especially into U.S. waters Non-native Asian clams are spreading rapidly across parts of Lake Tahoe, often accompanied by stringy mats of bright green algae, and posing a new threat to the world-renowned mountain lake.— Tom Knudson, Sacramento Bee, 19 Aug. 2009 When jostled by turbulent water, an Asian clam "lifts off" the floor with its foot and releases a transparent mucous film that can catch the current like a sail. — Science, December 1984

Note: The Asian clam is often considered an invasive species in the U.S. where it is known to clog water intake pipes and compete with native species for food.