Sea fish. This kind of hippocampus is the largest, with a body length of 30 ~ 33 cm. The side is flat and the abdomen is quite convex. Dorsal fin18 ~19; Gluteal fin 4; Pectoral fin 18. Body ring 1 1+39 ~ 40. The trunk bone ring is heptagonal, the tail bone ring is quadrilateral, and the tail end is curled. Except for the head and abdominal spines, all spines on the body are short and blunt, showing tumor-like shape. The crown is low and small, with five short spines at the top and slightly bent back. Kiss is slender and tubular; The length of the kiss is slightly longer than the length of the back of the orbit, which is about equal to the length of the first spine at the back of the eye neck. Eyes are big and sideways. The eye spacing is smaller than the eye diameter and slightly convex. The nose is very small, two on each side, very close, in front of the eyes. Small mouth, located in the snout; When opened, it is slightly semicircular. Toothless. The gill cover is prominent and there is no radial ridge. The branchial foramen is small and located behind the head. The first spinous base is near the back of the neck. The central spine of the back of the neck has two prominent spines; There are infrabuccal spines; There are also short and blunt strong spines in the lower front of the pectoral fin base. The anus is located below the ventral side of the eleventh bone ring of the trunk. The body is scaleless and completely surrounded by the bone ring. All the thorns on the body are underdeveloped, short and blunt; Only the abdominal spine is prominent, and the lower abdominal spine is not prominent. The dorsal fin is long and developed, with 18 ~ 19 fin, which is located on the back of the last two bony rings of trunk and the first two bony rings of tail. The anal fin is short and located behind the anus. The pectoral fin is short and wide, slightly fan-shaped and stands sideways. No ventral fins and caudal fins. Each fin has no thorns and no branches. The body is yellowish brown with irregular or cystic white spots and stripes on the side.
2. Polypodidae
Larger, with a body length of 20 ~ 24 cm. Dorsal fin18; Gluteal fin 4; Pectoral fin 18. Body ring 1 1+35 ~ 36. The crown of the tree is not high, and there are 4 ~ 5 thin and pointed tips at the top. Kiss is slender and tubular; The length of the kiss is greater than or equal to the length of the head behind the orbit. The articular process of the bone ring and the head is particularly developed, but the process of the posterior caudal ring is not obvious. This is the characteristic that distinguishes the spiny hippocampus from other species. The body is yellowish brown, with a row of spots near the tip of dorsal fin, pale buttocks and pectoral fin, and the tip of mucro on the body is black.
Distributed in coastal areas of Guangdong and Fujian; Japan, Korea, India, Singapore, Indonesia, East Africa and the Red Sea.
3. Hippocampus-Syngnathidae
The body is also larger, with a body length of 20 ~ 24 cm. Dorsal fin17; Gluteal fin 4; Pectoral fin 16. Body ring 1 1+35 ~ 36. The crown of the tree is low, with five short and blunt thorns at the top. The kiss is tubular, and the length of the kiss is just equal to the length of the back of the orbit. Mucro on head, body ring and tail ring is not obvious. The body is dark brown, with tiny dark black spots on the head side, tiny silvery white spots scattered on the monkey body, black longitudinal stripes on the dorsal fin, and light colors on the buttocks and pectoral fins.
4. Polypodidae.
Large in size, with a body length of10 ~18 cm; Dorsal fin 20 ~ 21; Gluteal fin 4; Pectoral fin 17 ~ 18. Body ring 1 1+40 ~ 4 1. The crown is short and there are five short thorns at the top. The snout tube is shorter than the head length of12. The bony ring of body segment 1, 4, 7, 1 1, the bony ring of caudal segment 1, 5, 9, 13, 17, the dorsal junction is a raised ridge, and the dorsal spine is also larger than others. The body is yellowish brown or even dark brown, with radial brown stripes on the eyes, and there is a big black spot at the base of mucro at the back of the body 1, 4 and 7, which is an obvious feature of species such as the three-spotted hippocampus.
Distributed in the East and South China Seas of China, Fujian and Guangdong coastal areas (including Hainan Island). In addition, it is also distributed in the coastal areas of East Africa, Singapore and east indies.
5. Hippocampus japonicumKaup.
Small size, slightly flat side. Mucro on the head and spines on the body ring are well developed. The crown is small and the blunt spines are not prominent. Short kiss and small mouth. The gill cover is prominent and smooth, and the gill hole is small, which is located behind the gill cover. The body is dark brown and sometimes changes with the environment.