Azolla caroliniana

It is a small floating plant (0.8-1.2 inch, 2-3cm diameter) which can be used in an unheated tropical aquarium and even in external ponds. In good conditions, this plant will spread quickly and will need to be assessed regularly. It does not produce large roots but will provide a shelter for certain fish. In strong light conditions, it will take on an attractive rust red coloring. Promote strong ventilation to prevent condensation on the leaves or avoid the over-heating of the aquarium.

Azolla Caroliniana is a small aquatic fern that belongs to the Azollaceae family. It is also known as water fern or flying fern. This plant is native of the United States, where it is mainly found in ponds and marshes.