Scientists say they have discovered the world's smallest known fish in threatened(1) swampland(2) in Indonesia.

The fish, a member of the carp(3) family, has a translucent(4) body and a head unprotected by a skeleton(5).

Mature females grow to less than a third of an inch long. The males have enlarged pelvic fins(6) and muscles that may be used in reproduction, researchers wrote in a report published Wednesday by the Royal Society in London.

"This is one of the strangest fish that I've seen in my whole career,' said Ralf Britz, a zoologist(7) at the Natural History Museum in London. "It's tiny, it lives in acid(8) and it has these bizarre(9) fins. I hope we'll have time to find out more about them before their habitat(10) disappears completely."

The fish are found in an acidic(11) peat(12) swamp on the Indonesian island of Sumatra. Indonesian peat swamps are under threat from fires lit by plantation owners and farmers as well as unchecked(13) development and farming. Researchers say several populations(14) of the tiny fish have already been lost.

The previous record for world's smallest fish, according to the Natural History Museum, was held by a species of Indo-Pacific goby(15) one-tenth of a millimeter(16) longer.

According to researchers, the little fish live in dark, tea-colored water at least 100 times more acidic than rainwater. Such acidic swamps was once thought to harbor few animals, but recent research has revealed that they are highly diverse and home to many unique species.

科学家称他们在印度尼西亚濒临消失的沼泽中发现了世界上最小的鱼。

这种鱼属于鲤科，通体透明，头部几乎没有头骨保护。

周三，伦敦皇家协会发表报告说，成年雌鱼体长不足三分之一英寸，雄性的腹鳍和腹肌比较大，可能用于求偶繁殖。

伦敦自然历史博物馆的动物学家拉夫·布利兹说：“这是我从事动物学研究以来见过的最奇特的鱼之一。它们很小，生活在酸性水域中，还有这样奇特的鳍。我希望在它们赖以生存的环境还没有完全消失之前，可以对它们了解得更多。”

科学家们在印尼苏门答腊岛的一个煤炭沼泽中发现了这种鱼。印尼煤炭沼泽在农场主和农民大肆焚烧和无限制开发、农田开垦的威胁下，面临消失的危险。研究人员说这种小鱼的部分种群已经灭亡了。

自然历史博物馆说之前世界上最小的鱼是印度太平洋虾虎鱼的一种，体长十分之一毫米。

研究人员说这种小鱼生活在黑暗、茶色的水中，水的酸性比雨水强至少100倍。 此种酸性沼泽曾经被认为是极少数生物的栖息地，但是最近的研究表明它们孕育着各种独一无二的珍奇物种。