The Paideios is officially the world’s smallest fish. The Paideios’s name derives from the Greek word “Venus” and the Latin “Progenesis” which means “precocious reproduction”. It was discovered in the swamps in 1996 on the Indonesian island of Sumatra in water that has a PH level of 3. This is about 100 times more acidic than regular rainwater. Discovered only a decade ago on the Indonesian island of Sumatra, some mature female members reach only 7.9 millimeters. The largest Paideios found was a 10.3 millimeters mature female. Male Paideios average around 9.8 millimeters. When the Paideios was first discovered, it was believed to be the smallest vertebrate or back-boned animal on Earth. This title was lost however, when scientists found a minuscule species of frog “Paedophryne amauensis” in the New Guinea rain forest in 2009.
The Paideios is a member of the carp family and lives in the dark peat swamps & backwaters of Sumatra. The peat swamps & streams where they live, are highly acidic and brown in color. The swamps of Sumatra have been threatened by forest fires, logging and plantations in recent years, leading to the decline of some Paideios habitats. The Paideios is actually partially see-through, they have a reduced head skeleton, which leaves the brain completely unprotected by bone. The previous record for smallest vertebrate was held by an 8 millimeters species of Indo Pacific Goby. Resembling a larva more than it does an adult fish, the Paideios has a translucent body & small head with a skeleton that leaves the brain unprotected. Interestingly, the males have pelvic fins that can grasp.