The world’s smallest fish is 'Paedocypris progenetica', and was only recently discovered in the last decade. Scientists discovered it living in the forest swamps on the Indonesian island of Sumatra.

Mature females measure just 7.9 millimeters, less than one third of an inch. This tiny fish, a member of the carp family, has a partially see-through body and a reduced head skeleton, which leaves the brain completely unprotected by bone.

This tiny, translucent fish has the appearance of larvae, possesses some bizarre grasping pelvic fins, and lives in dark tea-coloured waters with an acidity of pH3, which is more than 100 times more acidic than rainwater.

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

This habitat is in much danger because the peat swamps have been damaged by large forest fires and they are still being threatened by industries such as logging and agriculture. As a result, several populations of 'Paedocypris' have already been lost.

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