Grayling are objectively one of the coolest fish out there, with that sail-like dorsal fin sporting blues and purples. They’re also uncommon in the Lower 48, historically only found in northern Michigan and the Missouri River headwaters in Montana. They’ve been extirpated in Michigan, though reintroduction efforts are underway. They still hang on in parts of the west, though they’re threatened by the usual suspects- drought, diversion, and introduced species.
The trouble with Montana grayling, from a conservation perspective, is that they are isolated populations of an otherwise widespread and abundant species. Arctic grayling as a species aren’t threatened with extinction, and so protecting Montana’s populations through mechanisms like the Endangered Species Act is at best a tough call for federal agencies. The Center for Biological Diversity recently sued the US Fish and Wildlife Service, hoping to shake loose more meaningful protections for this unique component of our western heritage.