The Collaborative International Dictionary of English v.0.48:

Prickleback \Pric"kle*back`\, Pricklefish \Pric"kle*fish`\, n.
   (Zool.)
   The stickleback.
   [1913 Webster]

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]

WordNet (r) 3.0 (2006):

prickleback
    n 1: small elongate fishes of shallow northern seas; a long
         dorsal fin consists entirely of spines
    2: 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]