Stickleback
Stickleback , noun
[Old English & Prov English stickle a prickle, spine, sting (Anglo-Saxon sticel) + back. See Stick, transitive verb, and compare Banstickle.]
(Zoology) 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.