Eichhornia crassipes

Species description

Care, breeding and tankmates

Plant profile

Placement

Midground

This is strictly a floating plant and must be placed on the water surface. Its long, feathery purple-black roots hang down into the water column, providing excellent shelter for fry and shrimp. It needs open space at the surface and should not be crowded by other floating species. It is ideal for open-top aquariums or ponds.

Botanical form

Rosette

It forms rosettes of glossy, rounded, leathery green leaves with distinctive spongy, bulbous leaf stalks that provide buoyancy. The submerged roots are long, dense, and typically dark purple or black, creating a beautiful contrast. Under high light in open setups, it produces spectacular, showy pale purple flowers with a central yellow spot.

Growth

Fast

The growth rate of water hyacinth is famously explosive under strong light and rich nutrients. It multiplies rapidly via runners, quickly covering the entire surface of an aquarium if left unchecked. Constant removal of excess plants is mandatory to prevent it from blocking light to submerged species. It is one of the fastest-growing aquatic plants known.

Substrate

High

As a true floating plant, Eichhornia crassipes does not require any substrate for anchoring. Instead, it develops a dense, feathery mass of dark roots that hang freely in the water column to absorb dissolved nutrients. While it does not root in the soil, its extensive root system serves as an excellent hiding place for fish fry and microfauna. Substrate type and depth are entirely irrelevant to the successful cultivation of this species.

Column fertilization

Recommended

Liquid fertilization is highly effective, as the plant relies entirely on its submerged roots to extract nutrients from the water. Dosing comprehensive fertilizers, especially those rich in nitrogen and potassium, will fuel its rapid growth. Iron supplements are also beneficial to keep the leaves deep green. It acts as a major competitor for column nutrients.

Root fertilization

None

Root fertilization in the substrate is completely irrelevant for this species, as it is a strict floater. It does not root in the substrate under any normal conditions. All required nutrients must be available in the water column.

Trimming

Regular

Trimming involves simply removing entire daughter plants or older, yellowing rosettes from the surface. The extensive root system can be trimmed back if it becomes too long or unsightly, though this may temporarily slow growth. Regular thinning out is critical to ensure light penetrates to the plants below. Do not let it form a dense, impenetrable mat.

Propagation

Runners

Propagation occurs naturally and prolifically through vegetative reproduction. The mother plant sends out horizontal stolons (runners) that quickly develop into new daughter rosettes. Once a daughter plant has formed a few leaves and roots, the runner can be cut to separate them. In ideal conditions, this process happens continuously.

Sensitivity

Moderate

The plant is highly susceptible to melting if the air above the water is too humid and stagnant, which often occurs under tight aquarium lids. It strongly prefers open-top tanks with good air circulation. It is also sensitive to extremely low nutrient levels, which cause rapid deterioration. Additionally, it requires intense illumination to maintain its bulbous stalks.

Layout role

Midground

In the aquarium, it is used exclusively as a floating surface plant to provide shade, absorb excess nutrients, and offer a root jungle for small fish. Its dark roots add a wild, natural aesthetic to the upper levels of the tank. It is heavily utilized in breeding setups or ponds where nutrient export is a primary goal. It must be managed carefully.