Propagating Riccia fluitans 'Floating' (Crystalwort)

How to propagate floating crystalwort, a rootless liverwort, by splitting the mass into pieces that float free or pearl with oxygen when tied under mesh.

Overview

Riccia fluitans is a bright green liverwort that normally grows quickly at the surface and forms thick mats on and under the water. It has no roots or true leaves, just a branching thallus, so it is naturally a floating plant whose name literally means 'floating'.

Any single branch or antler-like bud can reproduce into a large colony in proper conditions, which makes propagation simply a matter of splitting an existing mass and giving the fragments room and light.

Propagation Method

Propagate by splitting the clump into pieces. Each fragment continues growing on its own, so pulling apart a healthy mat instantly multiplies your stock. Fragments left to drift will spread across the surface; pieces pressed under plastic mesh can be grown as an attached carpet.

Step-by-Step

Scoop out a healthy portion of the floating mass.
Pull or cut it into several smaller pieces.
To keep it floating, simply release the pieces at the surface.
To anchor it, spread a thin layer over a stone and cover with plastic mesh.
Tie the mesh down and place it under bright light.

Conditions for Healthy Growth

Riccia develops dense, bright green mats positioned a few inches below bright light or in full sun. Under strong light and CO2 the thallus releases visible oxygen bubbles, the prized 'pearling' effect, while the floating mat also shelters fry and absorbs excess nutrients.

Light: bright; keep it close to the surface or strongly lit.
CO2: not required to grow, but drives pearling in a tied carpet.
Use: a retreat for young fry and a nutrient sponge.
Anchoring: optional, always via mesh rather than roots.

Trimming & Maintenance

Thin floating mats regularly so light still reaches the layers below and lower fish are not left in shade. Skim off excess growth at water changes and re-tie any carpet that has grown too thick before it detaches and floats away.

Common Challenges

Riccia is easily crowded out: duckweed can blanket the surface and shade it, and hair algae readily overtakes it. Keep competing floaters in check and remove algae promptly so the colony keeps spreading.