The U.S. Fish and Wildlife Service proposed Endangered Species Act protection today for the Barrens topminnow, a small fish found only in central Tennessee in clear, spring-fed streams on the Barrens Plateau.

Just five populations of the highly endangered fish survive in the wild southeast of Nashville, where the species is threatened by drought, pollution and predation by non-native mosquitofish. At last count there were fewer than 400 total inviduals.

"The Barrens topminnow was first proposed for Endangered Species Act protection more than 40 years ago, and this small fish now finds itself on the very brink of extinction," said Tierra Curry, a senior scientist at the Center for Biological Diversity. "I'm hoping this proposal will be the turning point that keeps it from being lost forever."

The topminnow is found in Cannon, Coffee and Warren counties. It lives in the headwaters of the Duck and Elk river watersheds, which are part of the Tennessee River drainage, as well as in the Caney Fork River system in the Cumberland River drainage. The fish grows to 4 inches long, has flashy colors and swims near the water's surface, where it preys on mosquito larvae and other insects.

The Barrens topminnow was proposed for Endangered Species Act protection with critical habitat in 1977, but the proposal was never finalized. In 1982 it was instead placed on a waiting list for federal protection. The Center petitioned the Service to add the species to the endangered list in 2010 and won a lawsuit in 2015 requiring the Service to issue a decision on the petition.

The fish declined from 14 known sites in the early 1980s to seven sites in the mid-1990s. It is currently found in only five sites. In an effort to prevent its extinction, captive-breeding populations are being held at Conservation Fisheries Inc. in Knoxville and at the Tennessee Aquarium Conservation Institute in Chattanooga. For recovery, mosquitofish need to be removed; then barriers need to be installed, and populations need to be closely monitored.

"It's not too late to save the Barrens topminnow, but the scientists working to save them desperately need more money to fund their recovery," Curry said. "Instead of trying to undermine the Endangered Species Act, Congress should grant all the money that's needed to fully fund the recovery of our nation's endangered species."

The southeastern United States is home to more kinds of fishes, crayfishes, mussels and salamanders than anywhere else in the world, but it is also a hotspot for extinction. Last week a freshwater snail from Georgia, the beaverpond marstonia, was determined to be extinct, joining more than 50 other southeastern species that have already been lost to history.

The Center for Biological Diversity is working to gain Endangered Species Act protection for nearly 400 southeastern species. Nationally, Center legal victories have led to Endangered Species Act protection for 193 species since 2011; five additional species have been proposed for protection, including the topminnow.