Tadpole /(?)/

Tad·pole

Tadpole

n.
  1. 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. (Zool.)
  2. The hooded merganser. (Zool.) [Local, U. S.]

Phrases & Compounds
Tadpole fish
See Forkbeard (a).