Garra andruzzii

Garra andruzzii is a small cave-adapted cyprinid fish endemic to Somalia. It was long the only species of the genus Phreatichthys, a name built from the Greek words for spring and fish. The fish is whitish because it has no pigment, is blind, has no scales and grows to a maximum length of about 6.2 centimetres. It is thought to have evolved in the cave environment over roughly two million years. It was the first animal found that does not reset its biological clock with the light of the sun. Its internal clock measures time with an extremely long period of up to 47 hours, and the fish is completely blind to all light stimuli. Two other cavefish live in Somalia, the cyprinid Barbopsis devecchi and the catfish Uegitglanis zammaranoi.