They are both members of the family Syngnathidae, which also includes seadragons.
Even though they look very different, they share several common features:
* Elongated bodies: Both seahorses and pipefish have long, slender bodies.
* Bony plates: Their skin is covered in bony plates, giving them a somewhat rigid appearance.
* Snout: They have a long, tubular snout that they use to suck up food.
* Male pregnancy: Male seahorses and pipefish carry the eggs in a brood pouch on their bellies.
So, the next time you see a seahorse, remember that it's closely related to its more streamlined cousin, the pipefish!