A genus of mussels in the family Dreissenidae, class BIVALVIA. They are found in both fresh and brackish water and are not native to North America. Accidentally introduced into the Great Lakes in 1986, they now proliferate widely throughout the United States.

A class in the phylum MOLLUSCA comprised of mussels; clams; OYSTERS; COCKLES; and SCALLOPS. They are characterized by a bilaterally symmetrical hinged shell and a muscular foot used for burrowing and anchoring.

Water containing no significant amounts of salts, such as water from RIVERS and LAKES.