The stickleback fish

  Stickleback is a common name for any of several small, acanthopterygian fishes belonging to the family Gasterosteidae and found in fresh and salt water throughout many temperate and subarctic regions of the North­ern Hemisphere. The stickleback is an edible, scaleless fish having a rather wide mouth filled with small, sharp teeth, and a head protected by hard bone. The body is protected in most cases by a series of bony plates. From two to fifteen nonconnected erectíle dorsal spines are present in front of the dorsal fin, the ventral fins being reduced to one spine and a small ray. The two-spined or three-spined stickleback, Gasterosteus aculeatus, is the most common member of the family, and is found in abundance in Europe, n. Asia, and North America; it attains a length of 3 inches. Spinachia spinachia, the fifteen-spined stickleback, attains a length of 7 inches and is native only to western European coasts. The most common American species is the fur-spined stickleback, Apelles guadracus, found along the coasts of New England.

  Sticklebacks are noted mainly for their curious habits during the breeding season. In early spring, the male begins to secrete large quantities of gluelike substance with which he pastes together numbers of aquatic plants to prepare a nest. The body of the male then turns blue and red, attracting numerous females, each of which deposits from 50 to 100 eggs in the nest. The male then drives the females away and guards the eggs untíl they hatch 10 to 20 days later.