Dianella is a little-known genus of small freshwater snails with a gill and an operculum, aquatic gastropod molluscs in the family Hydrobiidae.

[3] These are European freshwater snails; they occur in southeastern Europe, from northern Italy, through the Balkans, to the Black Sea and the Caspian Sea Their relatively big shell has an onic[check spelling] or turriform shape with a common, prominent, spiral sculpture.

The radula shows a rhachidian tooth with no basal cusps.

Their stomach has a caecal appendix at its pyloric end.

They have a Hydrobia-like central nervous system, a simple penis and a characteristic, big seminal receptacle at the end of a prominent spiral of the coiled oviduct.