Gliding gently through seagrass beds and coral reefs worldwide, seahorses are some of the ocean’s most unusual fish. With their horse-like heads, curly tails, and upright swimming posture, they look like something out of a fairy tale—but their most extraordinary trait is their role reversal when it comes to parenting: it’s the males who carry and give birth to the babies.

Seahorses have a unique body structure that sets them apart from other fish. They lack scales, instead having a bony exoskeleton that protects them from predators. Their prehensile tails can curl around seagrass or coral, anchoring them in place so they don’t get swept away by currents. Unlike most fish that swim by moving their tails, seahorses use their tiny dorsal fins to propel themselves, making them slow swimmers but excellent at hiding in their surroundings.

The seahorse’s mating ritual is a delicate dance. Males and females perform an elaborate courtship display for days, changing colors, swimming side by side, and linking tails. Once they pair up, the female deposits her eggs into a special pouch on the male’s belly. The male then fertilizes the eggs and carries them for 2–4 weeks, providing oxygen and nutrients until they’re ready to hatch. When the time comes, he goes into labor, contracting his pouch to release dozens of tiny, fully formed seahorse fry into the water.

Seahorses face threats from habitat loss, pollution, and the illegal pet trade. They’re also sensitive to changes in ocean temperature, making them vulnerable to climate change. Protecting seagrass beds and coral reefs—their natural habitats—is key to saving these quirky fish and their one-of-a-kind parenting style.