Scale bar = 1 mm Paedocypris is a genus of tiny cyprinid fish found in swamps and streams on the Southeast Asian islands of Borneo, Sumatra and Bintan.

In 1994, the same ichthyologists had already discovered in Sarawak (Malaysian part of Borneo) another miniature species of the same genus Paedocypris.

[6] Their miniature transparent bodies lack the typical features characteristic of adult fish, for instance a mineralised braincase, and it retains the postanal larval fin-fold along the ventral edge of the caudal peduncle, characteristic of fish larvae.

Paedocypris progenetica has been claimed to be the smallest known species of fish and vertebrate in the world, particularly before the description of the frog Paedophryne amauensis in 2012.

However, these survive only by sexual parasitism,[9] and the female individuals reach the significantly larger size of 50.5 mm (1.99 in).

[14] Paedocypris progenetica lives in the blackwater peat swamps of the Indonesian islands of Sumatra and Bintan.

[2][15] In Malaysia alone, it has been estimated that—in addition to Paedocypris—up to 15% of the freshwater fish species are associated with peat swamps,[2] and based on current destruction rates all Bornean and Sumatran peatlands may be gone by 2040.