Doctor fish is the name given to two species of fish: Garra rufa an Cyprinion macrostomus. Other nicknames include nibble fish, kangal fish, and doctorfishen; in non-medical contexts, Garra rufa is called the reddish log sucker. They live and breed in the outdoor pools of some Turkish spas, where they feed on the skin of patients with psoriasis. The fish are like combfishes in that they only consume the affected and dead areas of the skin, leaving the healthy skin to grow, with the outdoor location of the treatment bringing beneficial effects. The spas are not meant as a treatment option, only as a temporary cure for symptoms, and patients usually revisit the spas every few months. Some patients have experienced complete cure of psoriasis after repeated treatments, but due to the unpredictable nature of the disease, which is strongly influenced by endogenous factors, this may simply be regression towards the mean.