Species description

Care, breeding and tankmates

Plant profile

Placement

Floating

Salvinia natans should be left to float unhindered on the surface of the aquarium water. It strongly prefers areas with minimal surface agitation, as constant splashing will wet the tops of its leaves and cause them to slowly degrade and rot. When placed in calm water, it will quickly form an attractive, textured mat that provides excellent cover for labyrinth fish and shrimp. This placement naturally shades the tank, which must be considered when choosing submerged plants to grow beneath it.

Botanical form

Floating

Salvinia natans is a delicate, free-floating aquatic fern that features pairs of flat to slightly curved, oblong leaves sitting on the water's surface. These floating leaves are covered in distinct, stiff bristles (trichomes) that repel water and ensure the plant remains buoyant. Beneath the water, a third, highly modified leaf structure hangs downward, functioning identically to a root system for nutrient absorption and stability. This unique morphology perfectly adapts the plant to a life spent entirely on the water's surface.

Growth

Medium

In an environment with strong lighting and plenty of nutrients, Salvinia natans exhibits a remarkably fast growth rate. It is highly capable of covering a large water surface area in a matter of weeks, aggressively outcompeting algae for available resources. To maintain a healthy balance and allow light to reach the lower levels of the tank, aquarists must be prepared to harvest handfuls of the plant regularly. While not always as explosive as its cousin S. molesta, its growth is still impressively rapid.

Substrate

None

Because it is an obligate floating fern, Salvinia natans requires absolutely no substrate to grow successfully. Its nutrient uptake is handled entirely by finely divided, modified leaves that hang beneath the water's surface acting as roots. Whether your aquarium features sand, gravel, specialized aquasoil, or no substrate at all, it will not affect this plant in the slightest. This characteristic makes it a perfect addition to quarantine tanks or breeding setups where bare bottoms are common.

Column fertilization

Recommended

Liquid column fertilization is the only effective method for providing nutrients to Salvinia natans. A regular dosing schedule utilizing a high-quality, comprehensive liquid fertilizer is highly recommended to support its rapid growth and prevent deficiencies. The addition of supplemental iron is often necessary to keep the floating leaves looking robust and vibrantly green. Because it cannot feed from the substrate, consistent water column dosing is the key to long-term success with this species.

Root fertilization

None

Root fertilization provides absolutely zero benefit to Salvinia natans. The plant lacks true roots that penetrate the substrate, so inserting root tabs or using nutrient-rich soils will not aid its growth in any way. All required nutrients must be dissolved directly into the water column where its submerged, root-like leaves can readily absorb them. Aquarists can completely ignore the substrate when considering the nutritional needs of this floating fern.

Trimming

Regular

Maintenance involves physically removing excess plants from the water surface rather than trimming them with scissors. Scooping out a portion of the colony weekly prevents it from blocking too much light. Ensure that discarded plants are disposed of properly and never introduced into local waterways. Regular thinning keeps the remaining plants healthy and vibrant.

Propagation

Cuttings

Propagation of Salvinia natans is an effortless process that happens entirely on its own through vegetative fragmentation. The plant's brittle stems naturally break apart as it grows, and each separated piece quickly develops into a new, independent floating colony. This continuous dividing process allows it to spread rapidly across any available surface space. When thinning out the plant, simply scooping out the excess sections is enough to manage its propagation in the aquarium.

Sensitivity

Moderate

While generally hardy, Salvinia natans is sensitive to strong surface agitation and excessive splashing, which can sink or damage its delicate leaves. It also dislikes condensation dripping onto its surface in closed-lid aquariums. High humidity combined with poor ventilation can lead to leaf rot. Ensure adequate airflow above the water surface for best results.

Layout role

Floating, Background

In the aquascape, Salvinia natans serves to create a natural, shaded environment reminiscent of a tropical stream or pond. The dangling roots provide a sense of depth and offer excellent hiding places for fry and small fish. It helps to diffuse intense lighting, creating a softer mood for the tank. Additionally, it aids in biological filtration by absorbing excess nutrients.