The Collaborative International Dictionary of English v.0.48:

parrotfish \par"rot*fish`\ (p[a^]r"r[u^]t*f[i^]sh`), n.
   Any of several gaudy tropical fishes of the family Scaridae
   having parrotlike beaks formed by fusion of teeth.

   Syn: pollyfish.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

parrotfish
    n 1: gaudy tropical fishes with parrotlike beaks formed by
         fusion of teeth [syn: parrotfish, polly fish,
         pollyfish]