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  Channel NewsAsia 25 Jan 05
Miniature Asian fish sets a whale of a record

PARIS : Scientists from Europe and Singapore say they have discovered the world's tiniest fish -- a species that lives in peat wetlands in Southeast Asia and, when fully grown, is the size of a large mosquito.

The record-busting newcomer to the biodiversity book, Paedocypris progenetica, is a distant cousin of the carp, say the discoverers, who publish their findings on Wednesday in Proceedings of the Royal Society B, a British journal.

Skinny and transparent, the elusive fish lives in highly acid peat swamps on the Indonesian island of Sumatra and in the Malaysian part of Borneo that are threatened by forestry and agriculture.

These so-called "blackwater" swamps are a unique landscape of flooded trees growing in water-logged, soft peaty soil that is often several meters (10 feet) thick. The water is stained reddish-black, like very dark tea, appearing black at the surface. It is extraordinarily acidic, having a pH3 value of only three, the same as a sour apple.

The scientists needed a special stereoscopic microscope to accurately measure the fish. The smallest adult specimen they netted was a mature Paedocypris progenetica female, found in Sumatra, that came to just 7.9mm (0.31 of an inch) from nose to tail, making it not only the world's smallest fish but the smallest vertebrate too.

She nudged out the previous record holder, a marine fish of the Western Pacific called the dwarf goby (Trimmatom nanus), which comes in at 8mm (0.32 of an inch) at sexual maturity.

The team also found a related Paedocypris species, P. micromegethes, in Sarawak in Malaysian Borneo. At 8.8mm (0.35 of an inch), P. micromegethes is the second smallest freshwater vertebrate ever found.

The fish was discovered by Maurice Kottelat and Tan Heok Hui, who are researchers at the Raffles Museum of Biodiversity Research at the National University of Singapore. They were assisted by Ralf Britz of Britain's National Museum of Natural History and Kai-Erik Witte at the Max Planck Institute for Developmental Biology in Tuebingen, Germany.

Kottelat said P. progenetica has "a very rudimentary skull" which leaves the brain exposed. Evolutionary pressures have caused the fish to develop highly modified fins to survive in its special environment. Males also have a tough pad on the front of the pelvic girdle that may be used to help them clutch onto females during mating.

"The discovery of such a tiny and bizarre fish highlights how little we know about the diversity of Southeast Asia," said Kottelat. "This is all the more serious because the habitat of this fish is disappearing very fast, and the fate of the species is now in doubt." - AFP/ir

 BBC 25 Jan 06
Scientists find 'smallest fish'
By Roland Pease BBC science correspondent

Scientists have discovered the smallest known fish on record in the peat swamps of the Indonesian island of Sumatra. Mature individuals of the Paedocypris genus can be as small as 7.9mm (0.3in) long, researchers write in a journal published by the UK's Royal Society.

But they warn long-term prospects for the fish are poor, because of the rapid destruction of Indonesian peat swamps.

The fish have taken extreme measures to survive in extreme habitats - pools of acid water in a tropical forest swamp. Food is scarce but the Paedocypris - smaller than other fish by a few tenths of a millimetre - can sustain their small bodies grazing on plankton near the bottom of the water.

Human threat

To keep their size down, the fish have abandoned many of the attributes of adulthood - a characteristic hinted at in their name. Their brain, for example, lacks bony protection and the females have room to carry just a handful of eggs. The males have a little clasp underneath that might help them fertilize eggs individually. Being so small, the fish can live through even extreme drought, by seeking refuge in the last puddles of the swamp.

But they are now threatened by humans. Widespread forest destruction, drainage of the peat swamps for palm oil plantations and persistent fires are destroying their habitat. Science may have discovered Paedocypris just in time - but many of their miniature relatives may already have been wiped out.
links
Photos galore of the fish and inside stories on the discovery and Singapore's "Indiana Jones" who discovered them on the Raffles Museum blog
Related articles on global biodiversity
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