The Collaborative International Dictionary of English v.0.48:

Paddlefish \Pad"dle*fish`\, n. (Zool)
   A large ganoid fish (Polyodon spathula) found in the rivers
   of the Mississippi Valley. It has a long spatula-shaped
   snout. Called also duck-billed cat, and spoonbill
   sturgeon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Polyodon spathula
    n 1: primitive fish of the Mississippi valley having a long
         paddle-shaped snout [syn: paddlefish, duckbill,
         Polyodon spathula]