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前言在4亿年以前就有了初期的低等鱼类。鱼类是地球上种类最多的脊椎动物。有些鱼生活在温泉里,温泉的水温有时在50℃以上。有些鱼则生活在北极的水域里,温度刚好超过冰点。为了寻找产卵的地方,洄游鱼可以游上几千公里。有些鱼的嗅觉极为灵敏,成鳗便是如此。这其中,热带观赏鱼的色彩,往往比生活在海洋或湖泊里的其他鱼类的色彩要斑斓得多,各式各样绚丽多彩的条纹和花斑,不仅仅只是美丽,更重要的是为了生存而做的
Foreword 400 million years ago there was an early lowland fish. Fish is the most abundant vertebrate on earth. Some fish live in hot springs, hot springs sometimes above 50 ℃. Some fish live in the waters of the Arctic, just over freezing temperatures. Migratory fish can swim for thousands of kilometers in search of spawning grounds. The smell of some fish is extremely sensitive, as is the case of an eel. Among them, the color of tropical fish tend to be more colorful than other fish living in the sea or lake, a variety of colorful stripes and piebald, not just beautiful, more importantly, to survive And do it