Three-spined Stickleback

(Gasterosteus aculeatus)

Gasterosteus aculeatus, commonly known as the three-spined stickleback, is a small fish species belonging to the family Gasterosteidae. Here are some key characteristics and information about Gasterosteus aculeatus:

  1. Appearance: Three-spined sticklebacks are small fish, typically ranging from 4 to 10 cm in length. They have a slender body and are named for the three spines present along their back, which are used for defense.
  2. Distribution: This species has a wide distribution across the northern hemisphere, including freshwater and coastal marine habitats. They are found in Europe, North America, and Asia.
  3. Habitat: Three-spined sticklebacks are adaptable and can inhabit various environments, from rivers and streams to lakes, ponds, and coastal marine waters. They prefer areas with vegetation and cover, where they can find food and shelter.
  4. Behavior: They are known for their territorial behavior during the breeding season, with males establishing and defending nesting territories. They feed primarily on small invertebrates, larvae, and zooplankton.