Source : Webster's Revised Unabridged Dictionary (1913)

Opah \O"pah\, n. (Zo["o]l.)
   A large oceanic fish ({Lampris quttatus}), inhabiting the
   Atlantic Ocean. It is remarkable for its brilliant colors,
   which are red, green, and blue, with tints of purple and
   gold, covered with round silvery spots. Called also {king of
   the herrings}.

Source : WordNet®

opah
     n : large elliptical brightly colored deep-sea fish of Atlantic
         and Pacific and Mediterranean [syn: {moonfish}, {Lampris
         regius}]