The Floating Crinum is widespread in tropical West and Central Africa. In this regions, this onion plant grows under water in rivers and streams, even in the brackish water of the tidal zone. Its inflorescences with attractive white lily flowers rise over the water. Crinum natans is long known as a robust, large aquarium plant. Its to 1.4 m long and 2-5 cm wide, wavy, strap-shaped are a real eyecatcher in large tanks.
Crinum natans grows rather slowly and is not very demanding. It tolerates hard water with pH values up to 8. However the plant needs a high substrate layer (about 10 cm or more) for its strong root system. The onion should stick out from the ground, otherwise it may rot. The plant is nutrient-demanding and benefits much from bottom fertilization. Medium lighting is sufficient, but stronger light enhances a more wavy margin of the leaves. The favourable temperature range is about 22-30 °C. With time, daughter plants may appear on the base of the onion that can be detached for propagation.
This big underwater plant from tropical Africa is best placed in the midground to background of large tanks. It is especially appropriate for stream biotope aquariums; open tanks are also adorned by the beautiful emersed flowers that occasionally develop on the plant. As its leathery leaves remain unaffected by fish, Crinum natans is also suitable for Tanganyika and Malawi lake cichlid aquariums.