wonders

Scientists have discovered a fish living in forest swamps on the Indonesian island of Sumatra that is only 7.9mm long.

The species of fish belongs to the carp family and is called Paedocypris progenetica . It is the world's smallest vertebrate or backboned animal.

World's smallest vertebrate is a member of the carp family of fish. © Maurice Kottelat, Cornol /Raffles Museum

Living in acid

The tiny, see-through Paedocypris fish have the appearance of larvae and have a reduced head skeleton, which leaves the brain unprotected by bone.

They live in dark tea-coloured waters with an acidity of pH3, which is at least 100 times more acidic than rainwater.

'This is one of the strangest fish that I've seen in my whole career', said Ralf Britz, zoologist at the Natural History Museum.

'It's tiny, it lives in acid and it has these bizarre grasping fins. I hope we'll have time to find out more about them before their habitat disappears completely.'

Threatened swamps

The swamps were once thought to harbour very few animals, but recent research has revealed that they are highly diverse and home to many species that occur nowhere else.

In 1997 the peat swamps were damaged by large forest fires and they are still threatened by logging, urbanisation and agriculture. Several populations of Paedocypris have already been lost

The dwarf pygmy goby (Pandaka pygmaea) is a tropical freshwater fish of the family Gobiidae. It is one of the smallest fish in the world by mass, and is also one of the shortest freshwater fish. Mature males can reach up to 1.1 cm, while the females can grow up to 1.5 cm. Average weight is from 4 to 5 mg. It is known as bia and tabios in the Philippines.

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