The ocean is the main habitat of fish, from polarization to the equatorial waters from the coast into the ocean from the surface to 1,000 meters on the abyss of all marine fish sightings. The diversity of living environment, has led to the diversity of marine fish, but because of organization, structure, function, similar to produce a series of common characteristics. People under the common characteristics of fish to fish under the following definition: a fish gills to breathe with fins movement, the majority of body surface was a flake, in general with Wen Biao and to be able to change the marine invertebrates. From this definition,

all marine life in a breathing with gills, fins to swim in the water of life and life-long spine movement, whether it not like fish, fish certainly is. Such as the hippocampus, which the body from top to bottom did not feel it as people fish, the hippocampus may in fact have the characteristics of these fish, the fish is the letter: while some of the fish called the designation of marine life, UNIFEM Squid, abalone, a mollusk either, or belonging to mammals, although common to be called the fish, in fact, Nie no little fish.

Of marine fish may be back on a long history. 4th century BC, the Greek scholar Aristotle in his "Animals" a book records the survival of the Aegean Sea in the 115 kinds of fish and fish the structure, breeding, migration and other aspects of the system more Narrative. China is the world's development, use, the study of marine fish one of the earliest countries. Jiaozhou Bay in Shandong in 1975 to explore the banks of the tomb, confirmed that the Chinese yuan in the Neolithic Age, Le will be able to catch fish, Barracuda, black sea bream, blue sharks, and other point-of marine fish. In ancient writings, not only fish habits, the full account of fisheries and fish are the growth, reproduction and ecology of knowledge.

Modern marine fish research, is said to be from France and scholars GB Ju Weiye A. Walang Messina's "Natural History of fish", after all academics on the migratory marine fish, reproduction, growth and the distribution of resources And development for a lot of investigation and research, "Challenger", "albatross", "Dana" and other marine survey vessels of the most significant achievements. Since the 1950s, there was wide application of electron microscopy, high-tech satellite remote sensing of marine fish, physiological and ecological done a great deal of research, the 1950s China's marine fish to China conducted a large-scale census, look at the Fish has published a series of monographs, to fish the physical, ecological and genetic and other aspects of the research and development.

According to the survey. At present a total of 21 723 kinds of fish, marine fish of about 12,000 kinds. China's marine total number of 3,187 kinds of fish. The classification of these fish, compared the current program is divided into three.

First, Cyclostomata (Cyclostomata) is the most primitive fish, supreme mandible, jaw is also known as a category. No bare skin scales, a slender physique eel-shaped, bone cartilage to complete. Even without fins, no shoulder strap and belt, chordoma life there, Yuan vertebrae. Is not alone on the nose, from the embryonic form of the gills in a muscle in the capsule and opening in vitro.

Second, Chondrichthyes (Chondrichihyes). Full of bone within the bone, but often reinforced calcification, bone yuan any true: be a shield skin scales, no nudity or spike thorn scales. Naolu seamless. Gill each side of his head cracked, opening in vitro. Intestinal short, in a spiral valve. No fat. Fuqi-living inside a special form of mating, known as the fin feet. Line in fertilization. Luansheng, Ovoviviparous or viviparous, for the distortion-shaped tail, Chondrichthyes fish in the sea very wide distribution, but mainly to low-latitude waters.

Third, it is hard bone Pisces (Osteichthyes). Fish is in a high-level, and it is now the most prosperous of a gang. Within a bone ossification, the first permanent floating ballast of a film, the bones of bone joints. Was a hard surface of scales or scales, scales or no nudity. Gill, one pair of holes, gill interval degradation, gill to double the gills of the support, usually a fat, Qitiao more sub-section, intestines without spiral valve. Some fish have dorsal fin and ventral fin, the otolith solid. General for in vitro fertilization, no cloaca. Is now known around the world teleost some 18 000 kinds.

Marine Fish size may generally be divided into: ① torpedo type, size of such fish habitat in the middle of the waters, the most good at swimming, such as mackerel, mullet shuttle, tuna, and so on. ② arrow type. And torpedo-like, but the body is more extended, Ki fins after shift, the habitat in surface water, and be good at swimming, fish such as dogs, jaw-fish, etc., ③ side of the Chen Shui-bian. This size of the fish, dorsal-ventral axis height increase, a flat left and right, can be divided into grouper fish-Ji, overturned the fish-and fish-flounder flounder, respectively habitat near the bottom and bottom. ④ snake-type. This slender body shape of fish, for several circular cross section, the general habitat in the Harbour plant leaves, such as eel, Hailong, and so on. ⑤ zone. To extend the high side of the body of Chen Shui-bian, are not good at swimming, such as hairtail, Wong hairtail, and so on. ⑥ ball. This size of fish a few spherical body, the tail fin general underdevelopment, such as the tetrodotoxin me some fin fish, such as round, ⑦ vertical-Bian. This size of fish high dorsal-ventral axis narrow, flat shape, such as various ray, An s, and so on.

Fish fin fish is the main movement and balance organs. Jiaoou pair of fins, including Xiongqi, Fuqi; fragmentation of the fin is odd, including the dorsal fin, tail fin and Tunqi. Born in fish tail fin of the tail, and to promote the role, and so on, into the general round tail (from top to bottom of the same size, such as mackerel, tuna, etc.), distortion-shaped tail (of the ratio of the developed, will help up activities Such as sharks), the shape is the end (of the developed than in the leaves, contribute to downward movement, such as the Exocet).

Fish breeding methods are three kinds, namely Luansheng, Ovoviviparous and viviparous. The majority of the fish are Luansheng. Luansheng the fish will generally be mature eggs directly discharged into the water, for in vitro fertilization, and completed all the development process, but there are also a few fish (such as the number of sharks) is in fertilization, in vitro fertilized eggs still in development. Ovoviviparous of fish in general is in fertilized eggs, embryos in vivo development, but the embryo of nutrition is relying on its own supply of egg yolk, and no relationship between the mother, such as leukoplakia Star shark, white spot Squalene, the Japanese side shark, Xu pressure Ploughshares ray, the crucian carp and black (J & N). Viviparous fish is generally the mother, fertilized eggs in development, the embryo of a fertilized egg and maternal blood circulation in the contact, not only from its nutritional bulk of the yolk, but also to be the mother supply, such as the grey shark, and other stars. Fish spawning much higher than terrestrial vertebrates, the number of eggs because of the difference is the disparity between the different types, such as the number of tablets from the production of large eggs (such as the number of sharks) to 300 million floating production of eggs (such as Overturn fish). Generally do not lay eggs after the eggs for the fish, spawning large amount, such as sea bream producing about 1 million, eel-700 to 15 million; after spawning for fish eggs, eggs with less, such as Hippocampus spawning dozens to hundreds of tablets tablets.

Fish in various stages of growth rate and the size of the individual are very different. Research shows that the individual is the smallest fish-tiger shrimp fish, body length only 7.5-11.5 mm; largest up to 20 metres, such as whale sharks. Fish most rapid growth period, is usually sexually mature before then, feeding the fish bait for most of the mature product and fat reserves, only a small part for the length of growth, thus slowing down growth, the aging period , The length of an almost complete halt. The growth rate of all species are very different, and some fish hatched after a year long to be with the pro-like body size, some fish have to be long after many years with pro-like body size. In the life expectancy of fish species to another. Xia tiger fish branches and lanterns by some types of fish life less than one year, and some of the sturgeon fish can live to more than l00 years. China's coastal Zhejiang Province in the middle of the large yellow croaker has found that the maximum age was 29 years old, Xin Atlantic fish longest life expectancy is 23 years old. A number of mature fish in the one-time after-Wanluan, they all died, such as salmon and the European eel.

Because different types of fish feeding in the area but also a great deal of difference. If the perturbation to the nature of food, fish can be divided into Herbivorous fish, predatory fish and fish three kinds Omnivorous. Herbivorous fish, bait mainly to phytoplankton, fish heads such as shelter, Barracuda and blue-fish, etc.; predatory fish, generally object to feeding animals, the majority of marine fish are predatory fish, such as hairtail, Shiban Fish, large yellow croaker, the whale shark, basking shark, and so on. Omnivorous fish is feeding two or more different nature of food, animals, but also plants and water and underwater humus, such as grouper Ji, Ye scad, and so on. Fish of different feeding habits, a direct impact on their exercise intensity. General predatory fish exercise intensity, naturally fierce, and Herbivorous fish movement strength is weak, moderate temperament, the difference between diet and exercise intensity has a direct impact on the strength of the succulent fish.

Marine Fish is the friend of mankind, but also by the people-food. Fish for human beings to provide the opportunity to recuperate, protect the marine environment, for the survival of fish and create a good environment.