Linnaeus' original text (the type description) in Latin was very short, and reads as follows:[3] Nerita fluviatilis, n. 632: testa rugosa, labiis edentilis.

Habitat in Europa cataractis.Which means in English: "Nerita fluviatilis, number 632: the shell is wrinkled, there are no teeth in the aperture.

[5][22] Glöer (2002)[16] considered the type locality sensu Linnaeus as "Habitat in fluviis, Upsaliae ad molendinam Ulvam & alibi", but this would suggest a brackish water environment.

[25] This species is threatened mainly by river engineering and water pollution in densely populated regions.

[25] An analysis based on cytochrome-c oxidase I (COI) gene has shown that the recolonization probably originated in the Danube.

[25] The species occurs widely in Western Europe, and it is also widespread in the north of Ireland,[26] living in 10% of Irish streams and rivers.

[27] It lives in Great Britain,[26] including the Orkney Islands,[18] as well as in the Netherlands,[28] Belgium, Luxembourg, Liechtenstein, and Monaco.

[29] In central Europe, this species has been recently introduced in the Austrian Danube, where it was first recorded in Tulln, Lower Austria in 2001.

The indigenous distribution of T. fluviatilis included all of the large rivers: Rhine, Main, Moselle, Neckar, Weser, Elbe and Oder.

[40] In Southern Europe, Theodoxus fluviatilis lives in Albania,[2] Bosnia and Herzegovina,[2] Romania,[2] Bulgaria,[2] Slovenia,[2] and Croatia.

[41] In Macedonia and Albania it occurs in Lake Ohrid (which spans the border of the two countries) as the subspecies Theodoxus fluviatilis dalmaticus.

[17] It can also be found in Iran, in the provinces of Kerman, Gilan, Mazandaran, Fars, Hormozgan, Lorestan and Khorasan.

[24] In Africa this species occurs in Algeria,[44] and possibly (or probably) in Morocco, where there are records which some authors consider to be reliable.

[47][48] Bunje (2005) hypothetized that the ancestral range of Theodoxus fluviatilis was the Ponto-Pannonian region (southern Ukraine, Romania and Hungary).

[11] In 2002, German malacologist Peter Glöer summarized the distribution of this species during the Pleistocene and Holocene epochs.

[16] The shell of Theodoxus fluviatilis is somewhat depressed (with an usually low spire), strongly calcified, and has 3–3.5 whorls (including the protoconch).

[5] Shell coloration and patterns are very plastic in all species of the genus Theodoxus and these qualities may be influenced by factors like ionic composition of water, type of substratum and nutrition of individuals in various habitats.

[44] Shells of specimens of Theodoxus fluviatilis from Northern Europe are ornamented with a pattern of white, drop-like spots on a dark or red background.

[44] Though the coloration and patterns of the shells cannot be relied upon to identify specimens, opercular characters can be used for a proper identification of Theodoxus fluviatilis.

[44] The calcified operculum of T. fluviatilis is D-shaped, light reddish with a red margin, bearing a broad rib (also called a ridge) on its inner surface.

[44] There is sexual dimorphism on the border of the rib shield of the operculum, which is straight in females, but curved in males.

[27] The species easily attaches itself to stones, which allows it to live in fast-running waters and in wave zone in lakes.

[35] The ability of Theodoxus fluviatilis to live in freshwater and also in brackish water demonstrates the phenotypic plasticity of this species.

[26] Theodoxus fluviatilis serves an indicator species for river monitoring (in Germany); however the spreading populations also have a high tolerance for degraded habitats.

[18] This species, together with the isopod Saduria entomon, have been found to be a dominant part of the fauna biomass in the central and northern Baltic Sea.

[18] Theodoxus fluviatilis dalmaticus in Lake Ohrid can reach population densities up to 6412 snails per m².

[20] The species was found in population densities of up to 9000 snails per m² in a spring of the Anços river in Central Portugal, where there is a stable temperature of 15.3–16.6 °C, which allows continuous reproduction in Theodoxus fluviatilis.

[58] Theodoxus fluviatilis feeds mainly on diatoms living on stones,[18][35] scraping biofilms and also consuming detritus.

[59] Peters and Traunspurger (2012) studied the effect of the grazing of Theodoxus fluviatilis on epilithic meiofauna and algae.

[60] Theodoxus fluviatilis is gonochoristic, which means that each individual animal is distinctly male or female, and cross-fertilization can occur.