Potamon fluviatile northeastern Greece. In mainland Greece, "P. fluviatile" is found in the drainages of the Axios, Thyamis, Aheron and Arachthos, Pineiós, Piros-Tethreas, Pamisos and Evrotas rivers. In the Ionian Islands, "P. fluviatile" is known to occur at only one site on Corfu, as well as on Kefalonia, Lefkada and Zakynthos. In the Aegean Islands, it is found on Skiathos and Skopelos (Sporades), on Euboea and Skyros, and at a single site on Andros in the Cyclades. "Potamon fluviatile" is at the western distributional limit of the genus "Potamon". Other species in the genus occur through Eastern Europe and the Middle East,
Potamon fluviatile six "nationes", or "tribes". Natio "fluviatilis" was found in northern Italy, natio "tarantium" in southern Italy, and nationes "thessalonis", "kühnelti" and "laconis" were found in parts of Greece. The geographical distribution of natio "leucosis" was not reported, and it was suggested that a further (undescribed) tribe inhabited the Greek island of Andros. Despite this wealth of infraspecific taxa, they are rarely used by scientists, and some have questioned directly the value of defining infraspecific taxa within "P. fluviatile". In 1990, the population on Malta was described as a separate subspecies, "Potamon fluviatile lanfrancoi", and that taxon has become a conservation