Hypostomus luteus, also known in the pet trade as the golden sailfin pleco, is an armored catfish in the genus Hypostomus of the family Loricariidae. Very rare and beautiful plecos from South America. They are found in Northern Argentina on the border of Brazil living in the Rio Uruguay. They live in the fast flowing water feeding on the algae. They transition in from juvenile color to adult color. The transition is categorized into 3 phases. Phase 1 - They are all black with yellow spots. Phase 2 The black on the body starts to fade and golden yellow starts to show on the fish. Usually golden starts from the tail and works its way forward on the body. Phase 3 the fish has lost majority of the black and yellow has developed throughout the body.