Monosolenium Tenerum (Monosolenium tenerum) Care Guide
A flat-growing liverwort with attractive branching dark-green thalli that form soft cushion-like masses on hardscape.
Compiled by Aquairi from published sources · Published · Updated
Overview
Monosolenium tenerum is an aquatic plant in the family Monosoleniaceae. A flat-growing liverwort with attractive branching dark-green thalli that form soft cushion-like masses on hardscape. Easy to grow but fragile — its brittle structure breaks easily when disturbed, so it should be placed in calm areas of the tank.
Taxonomy
- Family: Monosoleniaceae
- Genus: Monosolenium
- Scientific name: Monosolenium tenerum
- Other names: Pellia, Flat Moss
Habitat
A liverwort of East Asia recorded from India, Nepal, China, Taiwan, Japan (including the Ryukyu Islands) and Hawaii. Naturally terrestrial on moist shaded soils; long known in the aquarium hobby under the misnomer "Pellia".
Growth requirements
- Light: low (≈30-50 PAR at substrate)
- CO2: optional (CO2 improves growth and coloration)
- Temperature: 18-26 °C
- pH: 6-7.5
- GH: 2-12 °dGH
- Nutrient demand: low
- Growth rate: medium
- Difficulty: beginner
Placement
- Maximum height: 5 cm
- Trim every: 21 days
Propagation
In cultivation the plant is propagated by vegetative division or fragmentation.
Propagating Monosolenium tenerum (Pellia)
Overview
Monosolenium tenerum is a weedy liverwort from East Asia and the only species in its genus and family. In the hobby it is widely sold as Pellia or Pelia, though it is mistakenly known by that name, and aquarists value its branching dark-green thalli that form soft, cushion-like masses on hardscape. It has a low light demand, a low CO2 requirement and a medium growth rate, and once established it is very undemanding.
Crucially, this liverwort lacks roots, so it will not anchor itself to anything. It is also brittle: pieces break off easily, which makes it both fragile to handle and very simple to propagate.
Propagation Method (Division)
Pellia is propagated by breaking the clump into pieces. Because the plant has no rhizoids and never attaches on its own, every piece you separate must be physically held in place against stone or wood until it grows into a new cushion.
Step-by-Step
- Lift a healthy clump and gently break it into smaller pieces; the brittle thalli separate readily.
- Place each piece on a stone or piece of wood, or nestle it in small clumps among other plants.
- Secure it with fishing line, fine mesh or a small weight, since it cannot hold on by itself.
- Keep the pieces in a calm area with low light; intense flow will tear the brittle thalli apart.
- Allow the clumps to thicken before relocating or re-trimming them.
Conditions for Healthy Growth
- Light: low demand; it grows well without intense illumination.
- CO2: low requirement, with only minimal supplementation needed.
- Placement: calm, low-flow areas that spare the brittle structure.
- Anchoring: always tied or weighted to hardscape because it has no roots.
Maintenance
Trim the cushions to keep them compact; the fragments that naturally separate can simply be repositioned and tied down as new plants. Handle gently during every step, as the brittle plant breaks off easily when disturbed.
Common Challenges
- Floating away: with no roots it never self-attaches, so loose pieces drift unless secured.
- Breakage: the brittle thalli snap easily, so keep it in calm water and handle carefully.
- Misidentification: it is often confused with true Pellia and with Susswassertang, so confirm what you have.