The Chiapas Swordtail (Upland Swordtail) or Xiphophorus alvarezi is a livebearing freshwater fish of the Order Cyprinodontiformes, family Poeciliidae, and genus Xiphophorus. It is, therefore, in the same genus as the Common Platyfish and the Swordtail. Xiphophorus means sword-tail in Greek. The Chiapas swordtail was discovered and first described by Donn E. Rosen in 1960, along with four other species of Xiphophorus.