Hippocampus belongs to fish. The hippocampus breathes through its gills. Seahorses generally like to live in slow-flowing coral reefs because they are not good at swimming. It is the collective name of several small warm marine fishes of the family Syngnathidae, and it is a small marine animal with a body length of 5 ~ 30 cm. Named after the head bends at right angles to the body, the head is horsehead-shaped, at an angle to the body shape, with a long tubular snout, a small mouth and dorsal fins, all of which are composed of fins. The eyes can move independently.

The hippocampus moves slowly, but it can capture copepods that move quickly and are good at hiding very efficiently.

The head of the hippocampus is flat, with two nostrils on both sides of the head. The head is bent at right angles to the body, and the fish is thick and flat, completely enclosed in the bone ring. The tip of the mouth is tubular, so it can't be opened and closed. It can only suck small animals in the water as food, and its eyes can rotate up and down, left and right, back and forth respectively. The chest and abdomen are prominent, and the trunk is composed of 10 ~ 12 bone ring, with a general body length of about 15 ~ 30 cm. The tail is slender and has four corners, and the tail tip can be curled and often curled; The head is bent, forming a large obtuse angle or right angle with the trunk, with a prominent crown at the top and a short tip at the crown end; Kiss is tubular; Small mouth, end position; Small branchial foramen

The whole body is completely wrapped by membranous bone, the dorsal fin is spineless, and there are no ventral fins and caudal fins. Dorsal fin is located between trunk and tail; Short gluteal fin; Thoracic fin developed; No caudal fin; Its fins are not easy to see with the naked eye. But with high-speed photography and careful observation, you can see moving thorns. These spines can move back and forth 70 times in one second. According to the wave from one end of the dorsal fin to the other, the hippocampus can ride this wave freely back and forth or up and down. The male fish has a pouch on the ventral side of the tail, in which the eggs hatch and can reproduce for 2-3 generations a year.