It's a wonder how this man manages to keep still while little fish nibble around his mouth during a spa treatment in Kangal, Turkey.

The fish, called Garra rufa obtusas, are also known as "doctor fish". They are native to rivers, streams, ponds and lakes in the Anatolian region of Turkey.

For over a century, these fish have been used for treating patients with chronic skin ailments such as psoriasis.

At modern-day spas, the water temperatures in the tank are kept high, which prevents the growth of nutrients that these fish feed on. As a result, they develop an insatiable appetite for eating up and clearing away the patient's dry, diseased skin.

At Kangal, psoriasis patients stay at the spa for 21 days and visit the fish pools twice daily for four-hour treatment sessions. The spa's mineral-rich water also helps to soothe their skin lesions.