World’s Smallest Fish: 7.9 mm (0.3-inch) long
On January 2006, the world's smallest fish was discovered on the Indonesian island of Sumatra: a member of the carp family of fish, the Paedocypris progenetica. It is the world's smallest vertebrate or backboned animal; only 7.9 mm (0.3 inches) long.
The title, however, is contested by 6.2 mm (0.2 in) long male anglerfish Photocorynus spiniceps (not technically a fish but a ***ual parasite) and the 7 mm (0.27 in) long male stout infantfish Schindleria brevipinguis.