|Northern tonguefish, Symphurus pusillus|
|Sub-families & Genera|
Tonguefishes are a family, Cynoglossidae, of flatfishes. They are distinguished by the presence of a long hook on the snout overhanging the mouth, and the absence of pectoral fins. Their eyes are both on the left side of their body, which also lacks a pelvic fin.
Some species have been observed congregating around ponds of sulphur that pool up from beneath the seafloor. Scientists are unsure of the mechanism that allows the fish to survive and even thrive in such a hostile environment.
- Froese, Rainer, and Daniel Pauly, eds. (2012). "Cynoglossidae" in FishBase. October 2012 version.
- Chapleau, Francois & Amaoka, Kunio (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 225. ISBN 0-12-547665-5.
- "Fish dance on sulphur cauldrons". BBC News. 14 December 2006. Retrieved 25 May 2010.