The red garra (Garra rufa), also known as the doctor fish or nibble fish, is a species of cyprinid that is native to a wide range of freshwater habitats in subtropical parts of Western Asia. This small fish typically is up to about in total length, but locally individuals can reach as much as . In the wild, Garra rufa feed on detritus, algae and tiny animals (arthropods and zooplankton). Since the early 21st century, this fish has been integrated into a spa treatment where they feed on the stratum corneum skin layer of patients with psoriasis. While the doctor fish treatment has been found to alleviate the symptoms of psoriasis, the treatment is not curative, and no cure for psoriasis currently exists. The use of the fish as a spa treatment for the wider public is still widely debated on grounds of efficacy and validity. Distribution, habitat and taxonomy As traditionally defined, Garra rufa is native to Turkey, The Levant, Iraq and Iran. Some of the main systems where it is found are the Kızıl, Seyhan, Ceyhan, Orontes, Queiq, Jordan, Tigris–Euphrates, Kor, and Mond river basins, but the species also inhabits other coastal river basins in the Levant and Iran, as well as the endorheic Lake Maharlu system. It lives in rivers, streams, canals, reservoirs, ponds and lakes, although it tends to avoid stagnant waters. It often is common or abundant, even in areas that are heavily influenced by humans like polluted canals. The taxonomy of this species has been labelled with uncertainty. As traditionally defined (sensu lato), there are some morphological variations over its relatively large range and it has been recognized for several years that it likely was a species complex. Several subspecies have been described, but their validity is questionable and in the last few decades authorities have generally not recognized them. Nevertheless, reviews published since 2014 have provided genetic and morphologic evidence for recognizing some of them as separate species, while other new species have been described from the species complex. This includes G. turcica (formerly a subspecies) from its Turkish range, except the Tigris–Euphrates system, G. jordanica (new species) from the northern Dead Sea basin, including the Jordan River, in Israel, Jordan and Syria, G. gymnothorax (formerly a subspecies) from the Karun, Balarud and Bashar systems in Iran, G. mondica (new species) of the Mond River basin in Iran, and G. amirhosseini (new species)