The hippocampus is not viviparous, but oviparous. Although the seahorse is peculiar in shape, it is actually a fish, so it is oviparous. And interestingly, seahorses are produced by males. Because male seahorses have child-rearing sacs, females will release eggs into them, combine with sperm and hatch slowly, and the male seahorses will not produce them until they hatch. It is worth mentioning that the seahorse is also the only animal among all animals whose offspring are produced by males.

1. Shape: As a fish, the shape of hippocampus is different from that of most fish. Ordinary fish have streamline shape, which is convenient for them to swim at high speed in water, while seahorse is an alien. Most of the time, it is in an upright shape, with its head and body at nearly right angles, looking like a horse's head and a small mouth.

2. Reproduction: Hippocampus reproduction is the most unique because it is the only animal in the world where males produce offspring. After mating, the female hippocampus releases eggs into the abdominal sac of the male hippocampus, and then the male hippocampus fertilizes them. The fertilized eggs will hatch here all the time before being released into seawater.

3. Swimming: Because of other shapes of hippocampus, it also has characteristics when swimming. Usually, the head is upward, the body is inclined and upright in the water, and the movement depends entirely on the dorsal fin and pectoral fin. In addition, their tails have the ability to curl and attach to the stems and branches of seaweed.