Kangal fish are fish which have adapted to the warm and mineral rich environment of the water in springs located in parts of Turkey and Westrern Asia. These naturally occurring fish often show up in outdoor pools at spas, which is when an interesting trait of the fish was observed: these fish like to eat dead or diseased skin, offering natural debridement to those who are willing to hop into the water with the fish.
These fish are also known as doctor fish or nibbler fish. Two separate species of fish appear to have developed the skin-eating behavior: Cyprinion mactrostomus and Garra rufa. Of the two, G. rufa seems to be the better-known. In Turkey, Kangal fish are protected, due to concerns that overharvest of the fish for the overseas trade could threaten the health of fish populations.
While the relationship between bathers and Kangal fish probably started out as a novelty, it has since become quite commercially profitable. Spas in Turkey, Japan, and the United States all offer Kangal fish treatments to clients at a premium price, sometimes as part of spa packages targeted at people with skin conditions like psoriasis.
These fish are not harmful, because they will not eat living tissue. The warm, mineralized water softens the skin, making it easy for the fish to nibble off the dead skin, leaving healthy living skin behind. For people with painful skin conditions, nibbler fish can bring temporary relief, especially if treatments are repeated on a regular basis. Others simply enjoy the novelty of a Kangal fish pedicure or full-body exfoliation.
In an environment with an assortment of foods to choose from, Kangal fish will usually prefer the food to dead skin. The skin-eating behavior probably arose in response to minimal available resources, which forced the fish to get creative about finding nutrition. Several other fish species exhibit this behavior in stressful conditions, suggesting that fish simply recognize a potential source of sustenance when they see it.
In addition to being kept in spas, these fish can also be kept in private aquariums. They can be a bit tricky to raise, because they require water with the right balance of minerals and the correct temperature. Several companies raise Kangal fish for sale to private collectors and spas.