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Fish: different types, definitions, photos, etc.

Fish are the oldest vertebrates, with a wide variety of species. There are about 32,100 named fish species distributed in various waters on the earth, of which there are about 2,500 species in China. Most of them live in seawater, with more than 1,500 marine fish and about 800 freshwater fish. In the past, fish were usually divided into two major categories, cartilaginous fish and bony fish, based on the similarities and differences in the properties of their bones. Characteristics: Aquatic animals (living in water). Skin covered with scales, belonging to cold-blooded animals. Cold-blooded animals with fins (can swim in water) and breathing with gills. Fertilization is external, mainly oviparous, some are viviparous and ovoviviparous.


Fish are a type of aquatic animals under the phylum Vertebrata, which mainly breathe through gills and use fins as the main organ of movement. Fish are the oldest and most diverse group of vertebrates on Earth, widely distributed in environments such as oceans, freshwater lakes and rivers.

  • Scientific name: Pisces (fish is no longer a strict scientific classification, but is used to describe fish in the phylum Vertebrata)

  • Main characteristics:

    1. Aquatic life: Fish live entirely in water.

    2. Gill breathing: Fish absorb oxygen from the water through their gills.

    3. Scale coverage: Most fish are covered with scales for protection.

    4. Function of fins: Use fins for swimming, balance and direction control.

    5. Poikilotherms: Fish body temperature changes with the external environment.

  • Ecological role:

    • Fish are in a key position in the food chain, both as predators and food sources.

    • Help maintain ecological balance, such as controlling algae populations and cleaning waters.

  • Evolutionary history:

    • Fish originated in the Cambrian period about 500 million years ago.

    • It was the first animal to have jaws and vertebrae, laying the foundation for the evolution of other vertebrates.


Fish classification table

Fish can be divided into three major categories based on anatomical and physiological characteristics: cartilaginous fish (such as sharks), bony fish (such as carp) and jawless fish (such as lampreys). The following is a detailed list of fish classification:

Classification levelOrderFamilyGenusExamples
Cartilaginous fishElasmobranchiiCarcharhinidaeCarcharhinusWhite Shark, Blue Shark


PristidaePristisSawfish


RajidaeRajaYellow Spotted Skate
Jawless FishCyclostomataPetromyzontidaePetromyzonLamprey


MyxinidaeMyxineHagfish
Bony fishesCypriniformesCyprinidaeCyprinidae (Cyprinus)Carp, grass carp


SiluridaeSilurusCatfish

PerciformesPercidaePercaPerch, largemouth bass


MoronidaeMoroneSeabass

AnguilliformesAnguillidaeAnguillaEuropean eel, Japanese eel

OsteoglossiformesOsteoglossidaeOsteoglossumDragon fish

ScombriformesScombridaeThunnusTuna, bluefin tuna

ClupeiformesClupeidaeClupeaSardines, herrings

CharaciformesCharacidaeAstyanaxPiranha, Astyanax

Main evolutionary history of fish

1. Origin

Fish are one of the oldest groups of vertebrates on Earth, and the earliest fish fossils can be traced back to the Cambrian period. Jawless fish (such as lampreys and hagfish) are the most primitive fish, followed by cartilaginous fish (such as sharks) and bony fish.

2. Cartilaginous fishes

Cartilaginous fishes (Chondrichthyes) include sharks, rays, etc. Their skeletons are made of cartilage rather than hard bones. These fish play an important role as predators in marine ecosystems.

3. Bony fishes

Bony fishes (Osteichthyes) are the most diverse group of fishes, with a hard bone structure. They have adapted to a variety of water environments, including freshwater and saltwater.

4. Jawless fishes

Jawless fishes are the earliest fishes, and representative species include lampreys and hagfishes. They have no jaws and rely on suction or parasitism for survival.


Ecological role of fish

  1. Important position in the food chain:

    • Predators: such as sharks maintain ecological balance.

    • Food source: such as small fish are food for many aquatic animals.

  2. Environmental health indicators:

    • The number and diversity of fish reflect the ecological health of water bodies.

  3. Resource Utilization:

    • As a source of protein for humans and a target for commercial fishing.


Conservation Status of Fish

  1. Overfishing: Many economic fish are facing the threat of extinction due to overfishing.

  2. Habitat Loss: Pollution and water development have caused serious damage to fish habitats.

  3. Climate Change: Temperature changes and acidified oceans are affecting the distribution and reproduction of fish.

  4. Conservation measures:

    • Establish aquatic conservation areas.

    • Implement sustainable fishing policies.

    • Protect endangered fish populations, such as sturgeons and eels.

Marine fishs Freshwater fish Cypriniformes Siluriformes
Luciocyprinus langsoni Vaillant

Luciocyprinus langsoni Vaillant

Luciocyprinus langsoni Vaillant,Luciocyprinus langsoni

Features:The body is long and stick-shaped, slightly flattened behind the dorsal fin, and the abdomen is round and without edges.

The Latin name of the single-striped Luciocyprinus langsoni Vaillant is Luciocyprinus langsoni Vaillant, which is an animal of the Cyprinidae family.Listed in the second level of the "List of National Key Protected Wildlife in China".Protect wild animals and stop eating game.Maintaining ec...

Gobiobotiahomalopteroidea Rendahl

Gobiobotiahomalopteroidea Rendahl

Gobiobotiahomalopteroidea Rendahl,eight-whiskergudgeon,Eight-bearded fish, pike

Features:The body is long and cylindrical, slightly flattened at the rear, with a slender caudal peduncle and 4 pairs of whiskers.

The Latin scientific name of the flat-finned loach is Gobiobotiahomalopteroidea Rendahl, and its foreign name is eight-whiskergudgeon. It belongs to the genus Gobiobotiahomalopteroidea of the family Cyprinidae and is endemic to my country.The flat-finned loach has high requirements for living condit...

Rhinogobio ventralis

Rhinogobio ventralis

Rhinogobio ventralis,Foreign fish, earthworm, long-fin goby

Features:The dorsal fin is long, the back of the body is dark gray with a slight yellow tint, and the abdomen is grayish white.

The long-finned goby, whose scientific name is Rhinogobio ventralis, is a fish of the Cyprinidae family and the genus Rhinogobio, with no subspecies. The long-finned snout goby has a wide range of activities in spring and summer, often foraging in rapids, deep canyons, and tributary outlets. I...

Rhinogobio nasutus

Rhinogobio nasutus

Rhinogobio nasutus,Big nose goby

Features:Very similar to the pigeon fish

The Latin name is Rhinogobio nasutus, which is an aquatic animal belonging to the class of ray-finned fish and is distributed in Gansu and other regions of my country.The specific information is unknown.Listed in the second level of the "List of National Key Protected Wildlife in China".Pr...

Coreius guichenoti

Coreius guichenoti

Coreius guichenoti,Square head water nose, water nose, golden loach, net mouth, twist, fat Tuo, water dense, round mouth copper fish

Features:The body shape is very similar to that of a black carp, but if you look closely, its mouth looks a bit like a carp, and it has a beard.

Coreius guichenoti, Latin name of round-mouthed copper fish, is a fish of Cyprinidae and genus Coreius.Round-mouthed copper fish is an important economic fish in the upper reaches of the Yangtze River. Common individuals are mostly 0.5 to 1 kg, and the largest can reach 3.5 to 4 kg. The artificial d...

Coreius septentrionalis

Coreius septentrionalis

Coreius septentrionalis (Nichols),Northernbronze-gudgeon,Pigeon fish, sand spit, sharp-mouthed water tuna, yellowhead fish (ancient name), northern copper fish

Features:Looks like a cute pigeon from the side

The Latin name of the Northern Bronze-gudgeon is Coreius septentrionalis (Nichols), and its foreign name is Northern Bronze-gudgeon. It is a freshwater fish of the Cyprinidae family of the Cypriniformes order. It is commonly known as the Pigeon Fish and is a species endemic to China.Northern copper...

Anabarilius transmontana

Anabarilius transmontana

Anabarilius transmontana,Mountain Whitefish

Features:The head is blunt, the body is flat, and the peritoneum is gray-black.

Anabarilius transmontana, a species of fish belonging to the Cyprinidae family, is endemic to China.Anabarilius transmontana is a small fish that likes to live in slow-flowing water environments and can grow and reproduce in lakes or rivers. It was once an important fishery target in Datun Lake in Y...

Anabarilius polylepis

Anabarilius polylepis

Anabarilius polylepis,Large white fish, peach white fish, multi-scale white fish

Features:The body is long and flattened, reproduces quickly, and grows fast.

Anabarilius polylepis, the Latin name of the multi-scale whitefish, is a fish species unique to Yunnan, China.The main food of multi-scale whitefish is aquatic plants, followed by small fish and shrimp. 1 winter age can reach sexual maturity, and in early spring every year, the parent fish swims in...

Luciobramamacrocephalus

Luciobramamacrocephalus

Luciobramamacrocephalus,longspiky-head carp,Blowgun, pointed-headed catfish, horse-headed catfish, duck-billed catfish, trumpet fish, catfish, catfish

Features:It has a pointed head, a long beak, and a slender body. It is commonly known as a blowpipe.

The Latin name of the carp is Luciobramamacrocephalus, and the English name is longspiky-head carp. It is a large predatory fish and a species endemic to my country.The carp is a large economic fish, fierce in nature, and likes to live alone. Individuals under 30 cm are generally active in the middl...

Gobiocypris rarus Ye et Fu

Gobiocypris rarus Ye et Fu

Gobiocypris rarus Ye et Fu,Raregudgeon,Golden white lady, ink line fish, rare goby

Features:Endemic to China, very rare

The Latin name of the rare gobiocypris is Gobiocypris rarus Ye et Fu, and its foreign name is Raregudgeon. It belongs to the genus Gobiocypris of the Cyprinidae family. There is only one species in this genus, which is endemic to my country.Rare goby mainly feeds on small aquatic invertebrates. The...

Tanichthys albonubes

Tanichthys albonubes

Tanichthys albonubes,White Cloud Mountain Minnow, Baiyunshan fish, Tang fish, Baiyun golden fish, golden fish, redtail fish, Guangdong crucian carp, Pan's crucian carp

Features:It is a very small freshwater fish that can tolerate cold weather.

The Latin name of the minnow is Tanichthys albonubes, and its foreign name is White Cloud Mountain Minnow. There is no subspecies.The minnow is bold, lively and gentle. Although distributed in the subtropics, it is still cold-resistant and can still live normally when the water temperature drops to...

Myxocyprinus asiaticus

Myxocyprinus asiaticus

Myxocyprinus asiaticus,,Rouge fish, grilled bream, yellow steak, leaf plate, red fish, purple bream, bird fish, blood steak, pink steak, etc.

Features:The Myxocyprinus rubripes is the only species of the family Myxocyprinus distributed in the Asian continent and has important academic value.

The Latin name of the mullet is Myxocyprinus asiaticus, and there is no subspecies.The ancestors of the mullet can be traced back to the Mesozoic era when dinosaurs ruled. The earliest ancestor of the mullet is called the primitive bony swim bladder fish. According to research, this fish appeared in...

Gyrinocheilus aymonieri

Gyrinocheilus aymonieri

Gyrinocheilus aymonieri,Wall Climbing Fish, Scavenger Fish, Algae Eater Fish, Double-Porifera

Features:There is a small gill opening above the normal gill opening, hence the name.

The Latin name of the diapsid fish is Gyrinocheilus aymonieri, which is endemic to Yunnan, China.The mouth of the diapsid fish forms a suction cup, which is used to attach to the surface of stones and shovel algae on the surface of the stones. As an ornamental fish, it is kept in an aquarium. It can...

Tenualosa reevesii

Tenualosa reevesii

Tenualosa reevesii,Hilsa herring 、Seasonal shad 、 Reeves’ shad,Shad, seasonal fish, salmon, salmon, Reeves's herring, etc.

Fish LC

Features:river-sea migratory fish, both freshwater and marine fish

The Latin name of the shad is Tenualosa reevesii, and its foreign names are Hilsa herring, Seasonal shad, and Reeves’ shad. There is no subspecies.The shad (Tenualosa reevesii) was first described in 1846 by the Scottish naval surgeon and naturalist John Richardson (1787-1865) in the Report on the...

Anguilla marmorata

Anguilla marmorata

Anguilla marmorata,Marbled eel、Giant Mottled Eel,Big eel, perch eel, flower eel, snow eel, king eel, black ear eel, reed eel, stream eel, stream slide

Features:It is called "the dragon among fishes" and has the property of "infinite growth"

The Latin name of the flower eel is Anguilla marmorata, and its foreign names are Marbled eel and Giant Mottled Eel. There are no subspecies.In 1824, French zoologist Jean René Constant Quoy (1790-1869) and French naturalist Joseph Paul Gaimard (1796-1858) reported on the Voyage autour de monde, en...

Acipenser schrencki

Acipenser schrencki

Acipenser schrencki,Amur Sturgeon,Seven floating fish, Heilongjiang sturgeon, Amur sturgeon, Acipenser schrenckii, Acipenser schrenckii

Features:It is the most valuable and high-quality rare fish among the existing sturgeons in China.

The scientific name of Acipenser schrencki is Acipenser schrencki, and its foreign name is Amur Sturgeon. It has the characteristics of large size, long lifespan, high survival rate of young fish, and fast growth rate. It is both ornamental and delicious.Acipenser schrenckii is an animal-eating fish...

Acipenser ruthenus

Acipenser ruthenus

Acipenser ruthenus,Sterlet,Acipenser

Features:The body color varies greatly, but the back is often dark gray-brown and the abdomen is yellow-white.

The Latin name of the small-bodied sturgeon is Acipenser ruthenus, and its foreign name is Sterlet. There is no subspecies.The small-bodied sturgeon is a freshwater sedentary fish that usually does not migrate long distances. The migratory species of sterlet start to migrate upstream to spawn during...

Acipenser nudiventris

Acipenser nudiventris

Acipenser nudiventris,Barbel Sturgeon、Ship Sturgeon.sturgeon, naked sturgeon

Features:Long cylindrical body, wide, flat abdomen

The Latin name of naked sturgeon is Acipenser nudiventris, and its foreign names are Barbel Sturgeon and Ship Sturgeon. There are no subspecies.The naked sturgeon is an advective, carnivorous fish. Naked sturgeons are divided into migratory populations and sedentary populations. Sedentary population...

Acipenser baerii

Acipenser baerii

Acipenser baerii,Siberian sturgeon,Acipenser siberianus

Features:There are two ecological types: semi-migratory and sedentary.

The Latin name of Siberian sturgeon is Acipenser baerii, and its foreign name is Siberian sturgeon. It has no subspecies.The appearance and biological characteristics of the Siberian sturgeon are similar to those of the small-bodied sturgeon (Acipenser ruthenus). In the Ob River, the Irtysh River (a...

Huso dauricus

Huso dauricus

Huso dauricus,kaluga sturgeon,sturgeon, amur sturgeon, sturgeon, sturgeon, sturgeon

Features:One of the ancient biota preserved from the Cretaceous period, it is the largest freshwater fish and is known as the "king of freshwater fish".

The scientific name of Dauricus sturgeon is Huso dauricus, and its foreign name is Kaluga sturgeon. It has no subspecies.As one of the ancient biological groups preserved in the Cretaceous period, the Dahurian sturgeon once lived on Earth with dinosaurs. Its primitive and simple appearance has hardl...

Dasyatis bennettii

Dasyatis bennettii

Dasyatis bennettii,Bennett's Stingray,Bennett's stingray

Features:It is a bottom-dwelling fish, closely related to sharks.

The yellow stingray's Latin name is Dasyatis bennettii, and its foreign name is Bennett's Stingray. It is a fish of the family Stingray and the genus Stingray.The yellow stingray (Dasyatis bennettii) was first described in 1841 by German ichthyologist and physiologist Johannes Peter Müller...