Overview of fish classification

The suborder Actillopterygii features: the base of the even fin is usually not fleshy (except for polyfin fish), the fin bone has only 1 row, and the fins are arranged in a radial manner. The upper and lower jaws and the cranial skull are covered with membrane bone. No internal nostrils. The vast majority of species have swim bladders. The gill fissure is covered by a bony gill and has an external gill hole on each side. The gill spacing degenerates. There is no cloaca, and the opening is in front of the cloaca. Usually there are no water spray holes. The body is hard scaled or round scaled or bare scaleless without fins. Because the upper and lower jaws are usually composed of toothed premaxilla, maxilla, tooth bones, etc., it is called the true mouth subclass Teleostomi.

Classification: Divided into 9 general headings 36 headings, China's domestic production of 9 general headings 28 headings, each heading search is as follows:

1 (2) The body is generally scaled or bare; the tail is crooked tail...........Sturgeon

2 (1) The body is ctenophoric, rounded, or bare; the tail is generally a positive tail

3(24) The maw is present with a swim bladder tube

4(21) The anterior vertebrae do not form a Weber's apparatus

5 (18) The body is not eel-shaped; it generally has ventral fins

6(13) The maxillary orifice margin often consists of the foremaxilla and the maxillary bone

7(12) Adipose fins

8 (9) The chin generally has a laryngeal plate; the development process has leaf-like larvae......... Sea carp

9(8) No laryngeal plates in the chin; no leaf-like larvae during development

10(11) The body is rounded or ctenophoric, with a lateral line; no auxiliary maxilla.....rodents

11 (10) The body is rounded scales, without lateral lines; there are auxiliary upper jawbones...........herring order

12(7) Generally has fat fins; there are lateral lines........................... Salmonids 13(6) The maxillary orifice margin is generally composed of a premaxilla

14 (15) Generally adipose fins and luminaires ........................... Lantern fish eye

15(14) Generally free of adipators and luminaires

16 (17) No scales on the body; no swim bladder; no teeth on the parasphenoid bone and tongue............... Cetebells

17 (16) The body is rounded with scales; there are swim bladders; there are teeth on the parasphenoid bone and tongue............... Arapaima

18(5) Bodies are eel-shaped or elongated; there are leaf-like larvae in the developmental process

19 (20) No ventral fins; no fins; Eels

20 (19) Have ventral fins; dorsal and fins often have fin spines; orbital sphenoid bones are absent... Dorsal spinosaur order

21(4) The first to fourth or fifth vertebrae form a Weber's apparatus

22 (23) The body is rounded or bare; the two jaws are toothless; there is a parietal and lower gill cap; the third and fourth vertebrae are not merged............... Cyprinids

23 (22) Naked or osseous plates; teeth on both jaws; no parietal and lower gill caps; merger of the third and fourth vertebrae......... Catfish

24(3) The presence of the swim bladder is absent

25 (54) The pectoral fin is normal and does not have a stalk at the base; the gill foramen is generally located in front of the base of the pectoral fin

26 (53) The nostrils do not enlarge, do not form long snouts, and do not have serrated edges; the pectoral fins do not dilate horizontally

27(52) The maxilla is not solidified with the premaxilla or healed as a bone beak

28 (51) The body is symmetrical to the left and right, with a glance on each side of the head

29(36) The dorsal fin is generally free of fin spines

30 (35) The dorsal and fins are mostly posterior; the ventral fins are generally ventral

31(34) Body without lateral lines; 2 on each side of the nostrils

32 (33) Fin without fin spines, 1 dorsal fin ... ... ...... Medaka order

33 (32) Dorsal, gluteal, ventral fins or with spines, dorsal fins 1 or 2 ... ... Silver Man Fish Eye

34(31) The body has a lateral line; 1 on each side of the nostrils..................... Jaw needlefish order

35 (30) The dorsal fin is generally longer than the fin, with 1-3 dorsal fins, 1-2 fins, and the ventral fins in the thorax or throat position............... Cod order

36(29) The dorsal fin is generally spiny

37 (42) The skull generally has an orbital sphenoid bone, if not, the ventral fin has 1 fin spine and more than 5 fins

38 (41) The ventral fins often have l-fin spines 3–13 fins; the lumbar bone is connected to the keybone

39 (40) Caudal fin main fin strips 18-19; fins generally have 8 fin spines......... Golden-eyed snapper

40 (39) Caudal fin main fin strip 10-13; fin with 1-4 fin spines, often showing obvious mackerel spines..................... Sea bream

41 (38) The ventral fin has no fin spines and has 1-17 fins; the lumbar bone meets the keybone... Moonfish

42 (37) The skull is orbital sphenoid

43 (44) The lumbar bone does not meet the keybone; the kiss is often tubular; the dorsal, breeal, and pectoral fins are mostly unbranched......... Prickly fish order

44 (43) The lumbar bone meets the keybone; the snout is generally not tubular; the dorsal, breeal, and pectoral fins are mostly branched

45 (46) Ventral fin ventral or subspectoral position; dorsal fin 2, far apart ..................... Mullets

46 (45) The ventral fin is present in the thoracic and laryngeal position; the dorsal fins are also close to each other if they are two

47 (48) The body is eel-shaped; the left and right gill holes are connected as a gill hole..................... Synoptera

48(47) Bodies are generally not eel-shaped; the left and right gill pores are separated

49 (50) The third suborbital bone is normal, not elongated, not contiguous to the anterior gill cap............................................. Percifomes

50 (49) The fifth suborbital bone is delayed, forming the undercular skeleton, which crosses the cheek and meets the anterior gill cap..................... Scorpionaeniformes

51 (28) Body asymmetry; both eyes are on one side of the head (left or right)............... Flounder Pleuronectiformes

52 (27) The maxilla and the foremandum heal into a bone beak; the ventral fin is generally absent..................... Tetraodontiformes

53 (26) The nasal bone expands, forming a long snout, with serrated edges and a lower mouth; the pectoral fin is horizontally dilated............... Mothfish order Pegasiformes

54 (25) The base of the pectoral fin is stalk-shaped; the gill foramen is located behind the base of the pectoral fin... ... ...... ...... Lophiiformes