A. torrentium grows to a length of around 10 centimetres (4 in), and has a smooth brown carapace, with an untoothed triangular rostrum; the underside is creamy white.

[4] The distribution of A. torrentium is centred on the Danube system, extending from the Olt River in Romania upstream to Germany and Switzerland and into parts of the Rhine and Elbe basins.

[8] Italy is at the south-western margin of the distribution of A. torrentium, with at least two populations in the Slizza drainage (a tributary of the Danube) near Tarvisio.

[4] Adult A. torrentium consume a variety of plant materials, including fallen leaves, while the juveniles chiefly feed on aquatic invertebrates.

[4] Natural predators of fully grown A. torrentium include foxes, bears, wolves, otters and badgers, while the young animals are targeted by fish.