Fourspine Stickleback

Apeltes quadracus

A photo of a fourspine stickleback fish, carrying eggs

Image by Graham Hegeman on Wikimedia, CC BY-SA 4.0

Physical: The fourspine stickleback is a 2.5 inch (6.4 cm) fish with three spines growing out of its back and a fourth spine attached to the dorsal fin. They’re mostly greenish brown, with a mottled pattern on their sides and silver white bellies. Males are typically darker than females.

Habitat: While the fourspine stickleback prefers saltwater or brackish water, it has a high tolerance for freshwater and can be found in some rivers as well. Their native range in North America spans from South Carolina up into Maine and parts of Canada. They are present year round.

Feeding: Sticklebacks are bottom feeders, picking through vegetation or sediment for microorganisms like diatoms, nematodes, and cyclopods.

Breeding: Their breeding season lasts from early May to late July. Males will build nests in their territory for females to come lay eggs in. Afterward, the male fertilizes the eggs and stays to guard the nest until they hatch six days later. They will care for newly hatched young until they can survive independently.

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