Up to 3,000 are packed into a square meter, according to researchers of the University of California, Davis.
The clams eat phytoplankton, which could prove to help keep the waters clear, but their waste also feed algae, which could make things murky.
And of course, whatever the clams eat mean less food for other creatures including native fish.
The good news is, the little buggers are edible. Known in Southeast Asia as the "prosperity" or "good luck" clam, they were originally brought by Asian immigrants in 1920 for food.
It's unknown how the clams got into the lake, but what's clear is that it's our duty to the ecosystem to eat as many as we can -- so pass the garlic and herb butter.
Jackson West wishes all the world's problems were so tasty.