The Collaborative International Dictionary of English v.0.48:

Greenfish \Green"fish`\, n. (Zool.)
   See Bluefish, and Pollock.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pollack \Pol"lack\, n. [Cf. G. & D. pollack, and Gael. pollag a
   little pool, a sort of fish.] (Zool.)
   (a) A marine gadoid food fish of Europe (Pollachius
       virens). Called also greenfish, greenling, lait,
       leet, lob, lythe, and whiting pollack.
   (b) The American pollock; the coalfish.
       [1913 Webster]