Riccia fluitans

Species description

Care, breeding and tankmates

Plant profile

Placement

Midground

It can be left to float freely at the water surface, where it provides excellent cover for fry. More commonly in aquascaping, it is tied down to rocks or meshes to form a bright green foreground carpet. If tied down, it requires intense lighting to reach the bottom of the tank.

Botanical form

free-floating submerged plant

Crystalwort is a floating liverwort consisting of bright green, dichotomously branching thalli. It completely lacks roots and true leaves, forming a dense, tangled mass of branching filaments. When submerged and pearling heavily with oxygen bubbles, it resembles a sparkling green jewel.

Growth

Fast

When provided with high light and CO2, its growth rate is explosive. It quickly multiplies, forming thick mats that double in size within a week or two. As a floating plant, it grows rapidly even without CO2 injection.

Substrate

None

Riccia fluitans is naturally a floating liverwort that lacks true roots and does not draw nutrients from an aquatic substrate. It absorbs necessary light and dissolved nutrients directly from the water column through its branching, crystalline structure. Although it can be cultivated as a foreground carpet, it must be mechanically weighed down with mesh or tied to flat rocks, as it cannot root itself into soil or sand. Without these physical restraints, pieces of the plant will detach and naturally rise to float at the water's surface.

Column fertilization

Recommended

Column fertilization is absolutely essential, as it relies 100% on the water column for its nutrition. Dosing a comprehensive fertilizer rich in iron and macronutrients will sustain its rapid growth. Insufficient nutrients will lead to pale, yellowish growth and eventual melting.

Root fertilization

None

Root fertilization is completely useless for this plant, as it has no roots. Even when tied to the substrate, it cannot access nutrients in the soil. All feeding must be done through liquid dosing.

Trimming

Regular

When grown submerged, it requires frequent, aggressive trimming to prevent the lower layers from rotting and causing the entire mat to float away. Use scissors to give it a close 'haircut' regularly. Be prepared to net out the thousands of tiny floating clippings after a trim.

Propagation

Cuttings

Propagation is incredibly easy and occurs naturally as the plant grows and breaks apart. To propagate manually, simply tear a clump in half and place it elsewhere. Every tiny fragment is capable of growing into a large mat.

Sensitivity

Moderate

It is quite sensitive to shading and requires direct, intense light to thrive underwater. It is also highly susceptible to liquid carbon (glutaraldehyde) overdoses, which will cause it to melt rapidly. Algae can easily entangle in its fine structure if nutrient balances are lost.

Layout role

Nano

Submerged, it is famous for creating bright, pearling foreground carpets or striking accents on midground stones, a style popularized by Takashi Amano. Floating, it serves well in breeding tanks or biotope setups to dim the light and shelter fish. Its vibrant, light green color is a standout feature in any layout.