freshwater and brackish
Ninespine Stickleback
Pungitius pungitius
Elongated, slender body shape with typically nine isolated spines along the dorsal fin. It features small scales or sometimes naked skin, pelvic fins modified into single sharp spines with soft rays, and a mottled olive-brown to greenish coloration with dark vertical bars or spots for camouflage.
- Habitat
- Found in northern hemisphere freshwater streams, lakes,…
- Size & weight
- Typically ranges from 5 to 7 centimeters in length, with…
- Diet
- Feeds on small aquatic invertebrates, including zooplank…
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Physical characteristics
Elongated, slender body shape with typically nine isolated spines along the dorsal fin. It features small scales or sometimes naked skin, pelvic fins modified into single sharp spines with soft rays, and a mottled olive-brown to greenish coloration with dark vertical bars or spots for camouflage.
Habitat & distribution
Found in northern hemisphere freshwater streams, lakes, ponds, as well as brackish and coastal marine waters. Prefers areas with dense aquatic vegetation and slow-moving or stagnant water.
Behavior
Solitary or loosely grouped outside of the breeding season. Known for active swimming among vegetation and complex territorial behaviors during reproduction.
Diet
Feeds on small aquatic invertebrates, including zooplankton, insect larvae, and small crustaceans, using a foraging strategy focused on micro-prey.
Reproduction
Males build a tubular nest out of plant debris glued together with a kidney secretion. They court females, coaxing them to lay eggs in the nest, and then fiercely guard and fan the eggs until they hatch.
Ecological role
Serves as an important prey species for larger fish and aquatic birds, while helping control populations of small aquatic invertebrates.
Similar species
Threespine stickleback (Gasterosteus aculeatus), which is distinguished by having three prominent dorsal spines and a broader body profile.
Identification tips
Look for the characteristic count of nine small, independent spines running along the back before the dorsal fin, combined with a slender body.
Interesting facts
Males develop a striking jet-black coloration during the breeding season to attract females and ward off rivals.