1) Fish 2) Flatfish 3) Tongue-fish 
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. This family has three genera with a total of more than 140 species. The largest reach...
• (n.) A flounder (Symphurus plagiusa) native of the southern coast of the United States.
any of the small marine flatfishes of the family Cynoglossidae, found in the tropics, especially in Asia. Tonguefish are flattened, drop-shaped ...
Tongue'fish` noun (Zoology) A flounder ( Symphurus plagiusa ) native of the southern coast of the United States. 
[n] - left-eyed marine flatfish whose tail tapers to a point
tongue-fish noun left-eyed marine flatfish whose tail tapers to a point; of little commercial value