Stickleback

from WordNet (r) 3.0 (2006)

stickleback
    n 1: small (2-4 inches) pugnacious mostly scaleless spiny-backed
         fishes of northern fresh and littoral waters having
         elaborate courtship; subjects of much research [syn:
         {stickleback}, {prickleback}]

from The Collaborative International Dictionary of English v.0.48

Stickleback \Stic"kle*back`\, n. [OE. & Prov E. stickle a
   prickle, spine, sting (AS. sticel) + back. See {Stick}, v.
   t., and cf. {Banstickle}.] (Zool.)
   Any one of numerous species of small fishes of the genus
   {Gasterosteus} and allied genera. The back is armed with two
   or more sharp spines. They inhabit both salt and brackish
   water, and construct curious nests. Called also {sticklebag},
   {sharpling}, and {prickleback}.
   [1913 Webster]