1. Fish form for spindle, can reduce water resistance body color. And for back deep abdominal shallow, have protective effects. <> 2. Br/fish skin have scale and mucous, have protection, reducing resistance; Also has the lateral-line, can be determined direction, feel the water
3. In athletic process fish fin is the sport organs, including body, promote stable caudal fin can move forward, control direction; Body has Biao, help in different layers of fish swimming <> br/between 4) gills are fish respiratory organs, gills in which many filaments to fish from the water intake oxygen.
<> br/ha, fish live in water, its size are suited for water environment: (1) the spindle, head and tail shaft is the longest, dorsoventrally axis is short, the shortest around axis. The whole fish head and tail pointed midway through the body shape and big, flies. (2) CeBian shape, the head and tail shaft short, about the shaft shorter, dorsoventrally shaft are relatively long, the body is shown around CeBian diamond. (3) flat oblate, about the shaft is longer, the head and tail shaft general, dorsoventrally axis is the shortest, fish body dorsoventrally compressed, or so spacious. (4) ManLi shape, the head and tail shaft special long, dorsoventrally axis and axial equal, short, around the head and tail larvae thin, pointed, trunk parts like a roots slender of round rods, like snakes. (5) fugu shape, form except the tail slightly prominent outside, almost approximate sphere. Br/> <<>
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2. Due to natural factors and human fishing influence, most fish can't complete their whole life process die. So, it is difficult for us to know its physiological life, can understand its ecological life. Is the usual practice in: according to caught some maximum individual (fish grow throughout their lives, the individual is bigger, the age is bigger also) body organization (such as the scales, thermolum inescence dose meter type fj427a1, fin bar, branch fins bone, gills cover bone, vertebrae and so on) rings to judge its life. Br/> << br/> generally speaking, fish life instead of individual size and sexual maturity age related. Fish body is larger, the later sexual maturity, service life is longer. From this point, the world's largest fish -- the whale's life should be the longest. Unfortunately, so far, people to its life knows nothing. According to reports, living in the Caspian sea and the black sea in the uefa Huang, weight of up to 15 kilograms, life expectancy above 100 years. While China's Yangtze river white sturgeon, life was close to 100 years. Many small fish, such as freshwater fishes in false tiger fish, the herring, whitebait, life will only about a year. Although fish life between difference is very big, but most fish life concentrated in 2 ~ 20 years between, including sixty concentrated in 5 ~ 20 years, to live to 30 years of fish can't more than 10% below, and 2 years of also only 5%. In our country, freshwater fish float fish: silver fins relate minnows, red fish, yellow YuBai, copper Sang fish, silver Gu, sand Li lifespan in 2 ~ 4 years between; A herring, grass carp, silver carps, it fish, crucian carp, mentioned fish, become warped mouth red guppy white, GuiYu lifespan in 7 ~ 8 years, the individual can live to 10 years. Seawater fish's short life easier. Br/> < <> in addition, br/with fish live in different surroundings, the life also has difference. Such as large, can live in zhejiang coastal 29 years, while in fujian, guangdong coastal, usually only 17 years of life, to hainan eastern waters, only live for nine years.
