Potamilus fragilis

Potamilus fragilis, previously Leptodea fragilis, the fragile papershell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. P. fragilis is one of the fastest-growing unionid species and the most abundant unionid species in Lake Erie. Its light-shelled morphology suggests an adaptation to deep water within lakes.

This species is found in the United States and Canada. Its natural habitats include streams, rivers and freshwater embayments.