Dreissenidae

Dreissenidae
Three shells of Dreissena polymorpha without the byssus, showing the range of color and markings
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Myida
Superfamily:	Dreissenoidea
Family:	Dreissenidae Gray, 1840
Genera
Dreissena Mytilopsis Congeria Rheodreissena

The Dreissenidae are a family of small freshwater mussels, aquatic bivalve molluscs. They attach themselves to stones or to any other hard surface using a byssus. The shells of these bivalves are shaped somewhat like those of true mussels, and they also attach themselves to a hard substrate using a byssus; however, this group is not at all closely related to true mussels, being more closely related to the venus clams (Veneridae).