Caridea, commonly known as caridean shrimp, is an infraorder of shrimp within the order Decapoda. They are found widely around the world in both fresh and salt water.
Carideans are found in every kind of aquatic habitat, with the majority of species being marine. Around a quarter of the described species are found in fresh water, however, including almost all the members of the species-rich family Atyidae and the Palaemonidae subfamily Palaemoninae. They include several commercially important species, such as Macrobrachium rosenbergii, and are found on every continent except Antarctica. The marine species are found at depths of up to 5,000 metres (16,000 ft), and from the tropics to the polar regions.
As well as the great variety in habitat, carideans vary greatly in form, from species a few millimetres long when fully grown, to those that grow to over a foot long. Except where secondarily lost, shrimp have one pair of stalked eyes, although they are sometimes covered by the carapace,…