stickleback

stickleback, common name for members of the family Gasterosteidae, small fishes, widely distributed in both fresh- and saltwaters of the Northern Hemisphere. Sticklebacks range from 1 1-2 to 4 in. (3.7–10 cm) in length and lack true scales; they are equipped with short, strong spines in front of the dorsal and on the ventral fins, the number varying with the species. These are used as offensive and defensive weapons, often against other sticklebacks during the breeding season, when the male is brightly colored and pugnacious. Each male constructs a roofed nest by gluing together bits of vegetation with a sticky secretion from glands near the kidneys. Under his persuasion, several females deposit eggs in the nest, which he guards jealously until well after the young hatch. Sticklebacks feed on smaller invertebrates and on the fry and eggs of other fish. Best known are the common stickleback, Eucalia inconstans, a coastal species, and the brook stickleback, a smaller freshwater variety. Sticklebacks are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Gasterosteiformes, family Gasterosteidae.

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stickleback

Any of about 12 species (family Gasterosteidae) of slender, scaleless fishes inhabiting temperate fresh and salt waters of the Northern Hemisphere. Sticklebacks grow to 6 in. (15 cm) long. They have a row of spines on the back, in front of a soft-rayed dorsal fin, and a sharp spine in each of the pelvic fins. They also have a slender tail base, a squared tail, and hard armour plates on their sides. The male builds a nest of plant materials and coaxes one or more females into it to lay eggs, fertilizes the eggs in the nest, and aggressively defends eggs and young.