Antarctic krill

Antarctic krill (Euphausia superba) is a species of krill that lives in the Antarctic waters of the Southern Ocean. They are shrimp-like and belong to the invertebrates.

Antarctic krill
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Euphausiacea
Family:	Euphausiidae
Genus:	Euphausia
Species:	E. superba
Binomial name
Euphausia superba Dana, 1850

They live in large groups, called swarms. Sometimes these swarms have a density of 10,000–30,000 individual animals per cubic meter.^[1]

They feed directly on very small phytoplankton, so they can use the energy that the phytoplankton originally got from the sun in order to sustain their life in the open ocean.^[2] They grow to a length of 6 cm, weigh up to 2 g, and can live for up to six years. They are a key species in the Antarctic ecosystem and are, in terms of biomass, probably the most successful animal species on the planet (approximately 500 million tonnes).^[3]

In aquaria, krill have been observed to eat each other.