Zebra mussels (Dreissena polymorpha)

Zebra mussels also know as Dreissena polymorpha got their name from the stripped pattern on their shell but it also varies and causes there to be no stripes and just light or dark colored shells.

They are native to Russia and were first introduced into the United States in the 1980's by transoceanic ships from western European ports discharging ballast water into lake St. Clair. Since their arrival zebra mussels have disrupted the natural  aquatic food chain of many bodies of water, also just like other mussels zebra mussels attach to hard surfaces like pipes

 and also the native mussels.

 with the spreading of these mussels the population of native mussels have severely reduced.
There are now  millions of these mollusks, and they have a rapid rate of reproduction and paired with no natural predator their numbers flourish.