空气中约含有21％的氧气,人每小时需要5—10米~3的新鲜空气才能满足对氧的需要,人脑缺氧15分钟就会坏死。鱼同样也离不开氧。水中溶解的氧满足不了鱼的耗氧需要时,鱼易生病,摄食量下降,严重时死亡。不同的鱼对氧的需要量不同,冷水性鱼、凶猛鱼类和野杂鱼高于温水性家鱼,所以鱼塘泛塘时这些鱼先浮头死亡。其次是 The air contains about 21% oxygen, people need 5-10 meters per hour 3 fresh air to meet the needs of oxygen, the human brain will be necrosis 15 minutes of hypoxia. Fish also can not do without oxygen. Dissolved oxygen in the water can not meet the oxygen consumption of fish needs, the fish is sick, food intake decreased, severe death. Different fish have different oxygen requirements. Cold-water fish, ferocious fish and wild trash fish are higher than warm-water domestic fish, so these fish first floated in pan ponds. Followed by