Salvinia oblongifolia

Salvinia oblongifolia is a Brazilian floating fern that is larger and more substantial than S. natans, producing elongated, oblong floating fronds with a bold surface texture of stiff, water-repelling cilia arranged in characteristic egg-beater clusters at their tips. This surface architecture is one of the most studied examples of the lotus effect in the plant kingdom. Its mats are denser and provide more substantial surface coverage than smaller salvinia species.

In paludariums with strong lighting and warm water, S. oblongifolia can cover a water surface very quickly, making periodic harvesting an important maintenance task. However, this also means it is an extremely efficient nutrient exporter and a valuable biological filter in densely stocked builds. It is slightly more demanding of warmth than S. natans and performs best in tropical paludarium temperatures.

Light: Medium to high; 2,500–6,000 lux; produces the most vigorous growth under strong lighting. CO2/Humidity: No CO2; requires calm or very gentle water surface to prevent the fronds from submerging. Fertilisation: No direct fertilisation required; all nutrients absorbed from water. Placement: Float freely on the water surface; thin regularly to maintain 50–70% surface coverage maximum. Propagation: Self-propagates rapidly by fragmentation; simply separate mats as needed.