Although they look very different from most fish, they share key characteristics like:
* Gills: They breathe underwater using gills.
* Fins: They have fins, though they are small and used for maneuvering rather than powerful swimming.
* Scales: Seahorses have bony plates that act as scales.
* Lay eggs: They reproduce by laying eggs.
Seahorses are actually classified as bony fish, meaning they have a skeleton made of bone, unlike sharks and rays which have skeletons made of cartilage.