Salvinia natans is a floating fern that grows quickly if there is sufficient nutrition and light. Light leaves are a sign of a shortage of micro-nutrients. It tends to take light from the plants at the bottom. Salvinia varieties have small hairs on their leaves, making them water resistant. Helps prevent algae by shading parts of the aquarium and using nutrients in the water. Grows very big in the wild and in optimum conditions. A decorative plant for open aquarium.