Floating Crystalwort
Riccia fluitans
Riccia fluitans, the floating crystalwort, is an aquatic floating plant of the liverwort genus Riccia which is popular among aquarists as a retreat for young fry and is used in live-bearing tanks. It can be found floating in ponds, and often forms thick mats on and under the water surface.
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Riccia_fluitans
Taxonomy & Classification
Kingdom
Plantae
Phylum
Marchantiophyta
Class
Marchantiopsida
Order
Marchantiales
Family
Ricciaceae
Genus
Riccia
Floating Crystalwort belongs to the family Ricciaceae, order Marchantiales, within the Marchantiopsida class.
Species Profile
Riccia fluitans, the floating crystalwort, is an aquatic floating plant of the liverwort genus Riccia which is popular among aquarists as a retreat for young fry and is used in live-bearing tanks. It can be found floating in ponds, and often forms thick mats on and under the water surface.
Floating Crystalwort (Riccia fluitans) faces severe decline due to widespread habitat destruction and degradation of freshwater ecosystems. Water pollution, eutrophication, and drainage of wetlands have eliminated many suitable aquatic habitats where this bryophyte species once thrived.
Key Facts
Habitat & Distribution
Threats
IUCN Red List: Critically Endangered
Floating Crystalwort (Riccia fluitans) faces severe decline due to widespread habitat destruction and degradation of freshwater ecosystems. Water pollution, eutrophication, and drainage of wetlands have eliminated many suitable aquatic habitats where this bryophyte species once thrived.
Agricultural runoff and chemical contamination
Habitat loss and wetland drainage
Water pollution and eutrophication
Climate change affecting water levels
Competition from invasive aquatic species
National vs Global Threat Status
How this species is assessed at the national level compared to its IUCN global status (CR).
| Country | National Status | Global Status | Comparison |
|---|---|---|---|
| EU | LCLeast Concern | CRCritically Endangered | Lower local risk |
| EU | LCLeast Concern | CRCritically Endangered | Lower local risk |
National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org
This page: SpeciesRadar (2025). Floating Crystalwort (Riccia fluitans). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/floating-crystalwort