The Collaborative International Dictionary of English v.0.48:

buffalofish \buffalofish\, buffalo fish \buffalo fish\n. (Zool.)
   1. any of several large carplike North American fish.
      [WordNet 1.5]

   2. (Zool.) Any of several large fresh-water fishes of the
      family Catostomid[ae] (also called suckers see [a

      href="http:]/www.state.ia.us/dnr/organiza/fwb/fish/iafish/sucker/sucker.htm">Sucker
      family), of the Mississippi valley. The red-mouthed or
      brown (Ictiobus bubalus), the big-mouthed buffalofish
      (Ictiobus cyrinellus, formerly called Bubalichthys
      urus), the black buffalofish (Ictiobus niger), and
      the small-mouthed buffalofish (Ictiobus bubalus,
      formerly called Bubalichthys altus), are among the more
      important species used as food.
      [PJC]

WordNet (r) 3.0 (2006):

Ictiobus niger
    n 1: fish of the lower Mississippi [syn: black buffalo,
         Ictiobus niger]