Oikopleura dioica is a species of small pelagic tunicate found in the surface waters of most of the world's oceans.

[3] Oikopleura dioica is widely distributed over the continental shelf in tropical and temperate waters in all the world's oceans.

Once the gelatinous net "houses" are too clogged to allow further filtration, they are then abandoned and drift down through the water to the seabed as "marine snow".

It has the typical chordate body plan, it is simple to keep and breed in the laboratory, it produces large numbers of eggs and the generation time is only four days at 20 °C (68 °F).

[7] In the Sars International Centre for Marine Molecular Biology, inbred lines have been developed using repeated matings of closely related individuals.