Three-spined Stickleback

A small fish found through much of the Northern Hemisphere, from California to Alaska and Chesapeake Bay to Baffin Island in North America, across Europe, and through Asia to the Bering Strait. It typically reaches only three to four centimeters, has a laterally compressed, scaleless body armored with bony plates, and three spines in front of the dorsal fin; breeding males develop bright red throats and bellies with blue eyes. It lives in fresh, brackish or salt water, favoring slow-flowing vegetated habitats such as ditches, ponds and sheltered bays. It is known for elaborate breeding behavior in which the male builds a nest from plant material and a self-produced substance called spiggin, courts a female, and fans the eggs to keep them oxygenated.