Mercuria similis is a species of small freshwater snail with an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.

[1] This species only tolerates very low salinities, and is perhaps better characterized as a freshwater snail.

high shell is fragile and translucent yellow-white in colour (but often coated with dark deposits).

Mercuria similis has a proportionately larger body whorl than other hydrobiids.

[citation needed] The shell is short-conical and 3.90–4.50 mm high (Vic-la-Gardiole, Hérault), with a large oval aperture.