Tadpole fish

from The Collaborative International Dictionary of English v.0.48

Forkbeard \Fork"beard`\, n. (Zool.)
   (a) A European fish ({Raniceps raninus}), having a large flat
       head; -- also called {tadpole fish}, and {lesser forked
       beard}.
   (b) The European forked hake or hake's-dame ({Phycis
       blennoides}); -- also called {great forked beard}.
       [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Tadpole \Tad"pole`\, n. [OE. tadde toad (AS. t[=a]die,
   t[=a]dige) + poll; properly, a toad that is or seems all
   head. See {Toad}, and {Poll}.]
   1. (Zool.) The young aquatic larva of any amphibian. In this
      stage it breathes by means of external or internal gills,
      is at first destitute of legs, and has a finlike tail.
      Called also {polliwig}, {polliwog}, {porwiggle}, or
      {purwiggy}.
      [1913 Webster]

   2. (Zool.) The hooded merganser. [Local, U. S.]
      [1913 Webster]

   {Tadpole fish}. (Zool.) See {Forkbeard}
      (a) .
          [1913 Webster]