Assiminea is a genus of minute, salt-tolerant snails with an operculum, aquatic gastropod mollusks, or micromollusks, in the family Assimineidae.

These are very small to medium large snails, between 2 and 13 mm).

The shape of the thin shells is somewhat ovately conical.

[2][3] The eyes are at the end of short, stout stalks.

They lay their eggs in the mud, and hatch as free-swimming larvae.