Riccia fluitans - Immersed Potted Plant

Riccia fluitans is a cosmopolitan, moss-like liverwort famed for its bright, lime-green cushions and dazzling oxygen “pearling” under strong light. Equally at home floating at the surface or tied down as a carpet, Riccia is a favourite in nature-style aquascapes and superb cover for fry and shrimp.

Physical characteristics

• Form: Fine, forked thalli (no true roots or leaves) forming loose mats or compact cushions.

• Colour: Fresh, vivid green that glows under intense lighting.

• Size: Individual strands 1–3 cm; mats can spread to cover large areas when secured.

Aquarium requirements

• Lighting: Medium–high to high. Strong light keeps cushions compact and boosts pearling.

• CO₂: Recommended for dense, bubble-laden growth.

• Fertilisation: Benefits from consistent micros (incl. iron) and moderate nitrates/phosphates; can feed entirely from the water column.

• Water parameters: pH 5.5–7.5; temperature 18–28 °C; soft to moderately hard water; gentle–moderate flow.

Planting & placement

• Floating use: Simply let it float; corral with floating rings if desired. Great as fry refuge or to shade delicate species.

• Carpet/wall use: Spread a thin layer between mesh (stainless/plastic) or under cotton thread on rocks/wood. Keep the layer thin for light penetration and to prevent lifting. Expect to re-tie every 3–6 weeks as new growth loosens.

Maintenance

• Trim regularly with scissors to keep pads low and even.

• Siphon loose fragments during water changes so they don’t clog intakes.

• Maintain stable CO₂ and nutrients to deter filament algae on the fine thalli.

Propagation

• Extremely easy: any fragment becomes a new plant. Trim, collect healthy pieces, and re-secure to mesh or let float to colonise.

Aquascaping use

• Foreground carpets in high-light tanks (classic Amano style).

• Floating curtains for soft, dappled light and surface interest.

• Shrimp/fry habitat—micro-structure traps infusoria and biofilm.

• Pairs beautifully with grey stone and fine-textured greens (e.g., Helanthium, Eleocharis).

Common challenges & tips

• Lifting carpets: Use very thin layers, fresh thread/mesh, and frequent trims; reduce excessive buoyancy by keeping growth tight.

• Algae on tips: Increase flow, ensure CO₂ stability, and balance light with nutrients.

• Filter clogging: Fit intake guards/sponges and net out strays after trims.

Riccia fluitans is a versatile, high-impact floating/carpet liverwort that delivers luminous green colour and spectacular pearling with strong light and CO₂. Easy to propagate and endlessly adaptable, it’s ideal for nature aquascapes, shrimp tanks, and breeders alike.

Origin
Country or continent where a plant is the most common. Cultivars arise or are bred in cultivation.

Growth Rate
Growth rate of the plant compared to other aquatic plants.

Height
Average height (cm) of the plant after two months in the tank.

Light Demand
The average or medium light demand of an aquarium plant is 0.5 W/L.

CO2 Demand
A medium need in CO2 is 6-14 mg/L. A high demand in CO2 is approx. 15-25 mg/L.