Phyllanthus fluitans

A free-floating aquatic plant native to the slow-moving waterways and flooded lowlands of Central and South America, from Mexico south to Argentina. It drifts across the water surface on buoyant, branching stems, sending down a trailing curtain of bright red roots — the trait that gives it its common name. In a paludarium or aquarium, it grows rapidly under bright light, forming dense mats that shade the water below and provide cover for aquatic life. Leaf colour shifts from pale green in lower light to a warm reddish-bronze as light intensity increases.