The Swan Mussel (Anodonta cygnea), is a large species of freshwater mussel, an aquatic bivalve mollusc in the family Unionidae, the river mussels.
Because of its morphological variability, and its wide range of distribution, there are over 500 synonyms for this species.
The shell is thin but large (approximately 10 to 20 cm) and rather flat, even at the umbo. The shell color is often pale greenish or brownish.
Its native distribution is European-Siberian. The geographical distribution of this species is from the British Isles east to Siberia, and south into northern Africa.
This species is found in rivers and lakes.