A tiny native darter famously at the center of the 1978 Tennessee Valley Authority v. Hill Supreme Court case — the species nearly blocked construction of Tellico Dam, eventually delayed but not prevented.
§ Quick facts
§ Encyclopedia
The snail darter is a disputed species of small freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. Emblematic of the debate over endangered species management in the United States, more recent phylogenetic studies indicate that it may actually be an eastern population of the stargazing darter.
Source: Wikipedia — Snail darter Licensed under CC BY-SA 4.0
§ Identification
Field marks. Small slender darter with brown back, paler belly; subtle vertical bars; large mouth for darter.
Similar species. Other darter species; expert ID required. Logperch (much larger). Sand Darter (different shape).
Voice. Silent.
§ Diet & behavior
Diet. Aquatic insect larvae, snails (giving the species its name).
Behavior. Famous in environmental history. ESA-listed (1975) discovery delayed Tellico Dam construction in Tennessee; case went to Supreme Court (TVA v. Hill, 1978) — court ruled species must be protected. Congress then passed a law specifically exempting Tellico Dam. Translocation to other rivers and discovery of additional populations have allowed the species to be downlisted from endangered to threatened; widely cited as example of how ESA implementation has evolved.
§ Range
Tennessee River system
§ Habitat
Clean cool streams with gravel bottoms
§ Threats
Dam construction, stream sedimentation, water-quality decline.
§ Conservation status
According to the IUCN Red List, the snail darter is currently classified as Least Concern.
§ What helps
Support endangered species protections. Donate to The Nature Conservancy Tennessee programs.
§ Further reading
- Wikipedia — Snail darter
- www.fws.gov — authoritative profile of Percina tanasi
- IUCN Red List · taxon 202511
- iNaturalist · taxon 49612
- GBIF occurrence records
- Encyclopedia of Life — Percina tanasi
§ Sources cited
- USFWS Snail Darter Recovery
- Tennessee Wildlife Resources Agency
- Environmental Defense Fund TVA v. Hill case history
- IUCN Red List 2013
