Three-spined stickleback

The three-spined stickleback is a small fish found in coastal and inland waters across the Northern Hemisphere. Scientists love studying it because it adapts easily to different environments and shows quirky behaviors. It’s a hardy little fish that thrives in both fresh and saltwater.

• Males build nests and perform dances to attract females during breeding.
• Some populations migrate from saltwater to freshwater to spawn.
• Their bodies change shape depending on whether they live in lakes or oceans.