The U.S. Fish and Wildlife Service plans to reopen a critical habitat comment period associated with the endangered spring pygmy sunfish, officials announced Friday.

The small, 1-inch fish inhabits a spring complex near the site of the future Mazda-Toyota Manufacturing U.S.A. site in Huntsville-annexed Limestone County. The FWS is now looking at designating a swamp in Wheeler National Wildlife Refuge because the fish was discovered there in 2015.

The Blackwell Swamp is a recreational area on the North Alabama Birding Trail. FWS officials believe the discovery of the second spring pygmy sunfish population decreases the species’ vulnerability. And because the swamp is on federally protected land, the designation would not interfere with private landowners or the business community.

“Establishing critical habitat raises awareness of the needs of the spring pygmy sunfish and other imperiled species and focuses the efforts of our conservation partners,” said a press release from the FWS. “It also alerts federal agencies, which are required under the ESA (Endangered Species Act) to make special conservation efforts when they fund or permit projects in those areas.”

Recent efforts to protect the fish have been largely led by the Center for Biological Diversity. The group filed suit against the FWS earlier this year over what it called a failure to protect the spring pygmy sunfish.

Elise Bennett, a staff attorney for the CBD, said Friday she was pleased the FWS is working toward protecting a critical habitat for the sunfish, but was concerned the agency’s proposal excludes some “vital areas” for the species.

“These little fish are going to be pushed even closer to extinction by urban sprawl if we don’t protect the last few springs and creeks where they can survive,” she said.

Those who want to comment on the proposal to designate a critical habitat for the spring pygmy sunfish, including the addition of Blackwell Swamp, can be submitted one of two ways:

• Online at http://regulations.gov; or

• Mail or hand-deliver comments to Public Comments Processing, Attn: FWS-R4-ES-2013-0010; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.