The Collaborative International Dictionary of English v.0.48:
Tonguefish \Tongue"fish`\, n. (Zool.) A flounder (Symphurus plagiusa) native of the southern coast of the United States. [1913 Webster]WordNet (r) 3.0 (2006):
tonguefish n 1: left-eyed marine flatfish whose tail tapers to a point; of little commercial value [syn: tonguefish, tongue-fish]