If you thought you were the champion of holding your breath under water as a kid, think again. Crucian carp, a fish closely related to the goldfish, can live months without oxygen, scientists have discovered.

These freshwater fish, generally inhabitants of the lakes and rivers of Europe and Asia, are able to change the structure of their gills to boost oxygen uptake, allowing them to survive when they are for all practical purposes starved of oxygen.

Additionally, their red blood cell hemoglobin, which transports oxygen, can bind oxygen to itself more strongly than in any other vertebrate.

Understanding the mechanism of how animals cope with oxygen starvation, called anoxia, could aid scientists solve similar problems in humans.

Anoxia related diseases are the major causes of death in the industrialized world, said Goran Nilsson, a professor at University of Oslo. Evolution has solved the problem of anoxic survival millions of years ago, something that medical science has struggled with for decades with limited success.

挪威科学家日前在英国实验生物学协会年会上说，生活在淡水中的鲫鱼（Crucian carp）是最强的“憋气高手”，因为即使是在没有氧气的情况下，鲫鱼仍然可以“好好地”活上好几个月。

据美国“生活科学”网站4月7日报道，鲫鱼是很类似于金鱼的淡水鱼，一般生活在亚洲和欧洲的湖河中。它们可以改变鱼腮结构来提高对氧气的吸收，以便在严重缺氧时保住性命。科学家们发现，鲫鱼血液中负责运输氧气的红细胞血色素也可以附着大量的氧气，它们的这种本领比其他任何脊椎动物都强。

了解动物如何应对缺氧危机，可帮助科学家们解决人类遇到的类似问题。挪威奥斯陆大学的高兰·尼尔森教授说：“与缺氧有关的疾病是造成工业化社会人类死亡的主要原因，医学界对此进行了几十年研究却成果甚微，而自然进化却早几百万年前就解决了缺氧存活的问题。”