The Collaborative International Dictionary of English v.0.48:

lizardfish \lizardfish\, lizard fish \lizard fish\n. (Zool.)
   Any of several mostly tropical marine scopeloid fish of the
   family Synodontidae having large mouths in lizardlike
   heads, especially the inshore lizardfish (Synodus foetens
   syn. Synodus poeyi) of Mideastern and Southern United
   States and West Indies; -- sometimes called sand pike.

   Note: A freshwater perch, the sauger, a different fish, is
         also called the sand pike.

   Syn: snakefish.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

lizardfish
    n 1: tropical fishes with large mouths in lizard-like heads;
         found worldwide [syn: lizardfish, snakefish, snake-
         fish]