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 sexual parasite) and the 7 mm (0.27 in) long male stout infantfish Schindleria brevipinguis.

10 of the world's smallest Animals, Animals, top animals in world, 10 animals

At 1.4 pounds and 4.9 inches tall, Ducky, a yappy short-coat Chihuahua from Charlton (Massachusetts, USA), holds the Guinness World Record for the world's smallest living dog (by height). Ducky succeeds Danka Kordak of Slovakia, a Chihuahua who measured 5.4 inches tall. The smallest dog ever, according to Guinness, was a dwarf Yorkshire terrier who stood 2.8 inches tall.

World's Smallest Snake: 10.1 cm (4-inch) long

Leptotyphlops carlae is the world's smallest species of snake, with adults averaging just under four inches in length. Found on the Caribbean island of Barbados, the species --which is as thin as a spaghetti noodle and small enough to rest comfortably on a U.S. quarter-- was discovered by Blair Hedges.