The Collaborative International Dictionary of English v.0.48:

Spadefish \Spade"fish`\ (sp[=a]d"f[i^]sh`), n. (Zool.)
   An American market fish (Chaetodipterus faber) common on
   the southern coasts; -- called also angel fish, moonfish,
   and porgy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Chaetodipterus faber
    n 1: deep-bodied disk-shaped food fish of warmer western
         Atlantic coastal waters [syn: spadefish, angelfish,
         Chaetodipterus faber]