The Yaqui topminnow or Sonora topminnow is a species of fish in the family Poeciliidae. Its scientific name is Poeciliopsis sonorensis, sometimes spelled sonoriensis; it is also sometimes considered to be a subspecies of Poeciliopsis occidentalis as P. o. sonorensis. This fish is native to Mexico, with a few native and introduced populations persisting in Arizona in the United States.