According to that report, the San Marcos gambusia only lived in parts of the upper San Marcos River and was last seen in the wild in 1983. It was first listed as endangered in July 1980.

“All currently available scientific data and field survey data indicate that this species has been extinct in the wild for over 35 years,” the Fish and Wildlife Service said.

Texas Parks and Wildlife says reduced flow of water from the springs and water pollution were threats to the fish’s population.