The three-spined stickleback (Gasterosteus aculeatus) may be small — just 4–7cm long and weighing around 1g — but it is a bold and surprisingly aggressive little predator. Found in ponds, lakes, rivers and wetlands across the United Kingdom, it feeds on invertebrates, tadpoles and even smaller fish.
Interestingly
Easily identified by the three sharp spines along its back, the stickleback has a brownish back and silvery sides. In spring, males transform dramatically, developing a bright red throat and belly with vivid green flanks. They perform an energetic courtship dance before building a carefully constructed nest from plant material. After the female lays up to 400 eggs, the male fiercely guards and fans them until they hatch — sometimes for up to four weeks.
With an average lifespan of 3–5 years, this diminutive fish is often the species most likely to be discovered during pond-dipping adventures — proof that even the smallest creatures can have big personalities.
