Smallest pufferfish
Malabar puffer, Carinotetraodon travancoricus
3.5 centimetre(s)
India ()

The world's smallest pufferfish is the Malabar puffer (Carinotetraodon travancoricus), also known variously as the dwarf or pygmy puffer among several other names, and is a freshwater species native to rivers in southwestern India's Western Ghats. It measures no more than 3.5 cm (1.4 in) in total length, often smaller (especially females), typically just 2.5 cm (1 in). On account of its extremely small size, it is known formally as a pea puffer, one of several such species housed within the genus Carinotetraodon. Some of them are only marginally bigger than this species. It was officially described by science in 1941.

Pufferfishes earn their name from their characteristic defensive behaviour. This involves a pufferfish filling its very elastic stomach with water until it has become much larger in size and almost spherical in shape, like a ball. Also, its outer body surface is covered in small sharp spines that stick outwards protectively when its body is thus inflated, thereby making it almost impossible for a potential predator to swallow a pufferfish that has adopted this defensive state.

The tetrodotoxin sequestered in the skin and organs of pufferfish also make them the world's most poisonous fish, though in some countries – such as Japan where it is known as fugu – it is still considered a delicacy. However, the dish must be prepared by a qualified chef who knows how to properly remove the limited edible parts of the fish.