Azolla filiculoides, Water Fern, is a member of the Azollaceae family and is a small, aquatic, free-floating fern. The fronds range in colour from green to deep red in colour.
A. filiculoides is common in dams and other still bodies of water where it forms dense carpets.
The species is found in all states except the Northern Territory as well as New Zealand and Central and South America.
A. filiculoides has been used for mosquito control in rice fields. The dense mat makes it hard for mosquito larvae to breath.
Propagation is by division but this happens without human intervention. Its biomass may double every 3-10 days. Excess plants may be removed with a net and used for compost.
The fern is not eaten by fish. A number of extinct species are known from the fossil record.