Gasterosteidae (stickleback; subclass Actinopterygii, order Gasterosteiformes) A small family of marine, brackish, and freshwater fish that tend to have torpedo-shaped bodies, a small mouth, small fins, and a series of separate sharp spines on the back preceding the dorsal fin. The body is scaleless, but may possess rows of scutes at the side. The well-known Gasterosteus aculeatus (three-spined stickleback) grows to 8 cm and can live in fresh as well as salt water. Gasterosteidae are found in temperate waters of the northern hemisphere.

stick·le·back / ˈstikəlˌbak/ • n. a small fish (family Gasterosteidae) with sharp spines along its back, able to live in both salt and fresh water and found in both Eurasia and North America. Its several species include the common and widespread three-spined stickleback (Gasterosteus aculeatus).

stickleback small spiny-finned fish. XV. f. OE. sticels sting, goad, thorn = OHG. stihhil goad, ON. stikill point of a horn, rel. to sticol steep, rough, f. Gmc. *stik- *stek- STICK1 + BACK1.

stickleback Small fish found in fresh, brackish, and salt water. It is usually brown and green, and may be identified by the number of spines along its sides and back. The male builds a nest of water plants, and drives the female into it. He then watches the eggs and cares for the young. Length: 8–11cm (3–4.5in). The 12 or so species include the three-spined Gasterosteus aculeatus. Family Gasterosteidae.

stickleback See GASTEROSTEIDAE.