Scientific Name: Riccia fluitans
Common Name: Riccia fluitans
CO2 Requirements: Moderate
Lighting Requirements: High
Plant Arrangement: Midground
Growth Rate: Fast
Plant Type: Floating
Water Hardness: Medium (GH = 9-13 dH)
Riccia fluitans is a versatile liverwort (cells of the plant carry only a single set of genetic information) used in planted aquariums since the 1970s. Riccia fluitans, commonly known as Crystalwort, is also a lush floating plant. Due to its versatility, it is often used for intricate aquascaping in show aquariums. This does not mean that it is for experts only; even novice aquarists can normally keep Riccia fluitans without any trouble. Riccia fluitans should not be kept with vigorous plant eaters, because this plant does not cope well with such attacks.
Popularized by the Japanese Aquascaper, Takashi Amano, Riccia fluitans has become a fan favorite of Nature Style Aquarium Aquascapers. The plant is composed of several tiny plants that can be nestled together to form a beautiful foreground carpet, or even a midground transitional plant.
Riccia fluitans can be found worldwide and is widely available in specialized aquatic plant stores, and through hobbyist’s forums. It occurs naturally in the wild as a floating plant in slow-flowing streams and ponds. Fish fry often take refuge within the network of interconnected moss-like strands.
Although Riccia fluitans is a naturally floating plant, following Amano’s lead, aquascapers from all over the world have netted and submerged the Riccia fluitans branches to grown them out into beautiful lush foregrounds and rock mounds. This liverwort is considered easy to grow, as long as there is ample light and carbon dioxide.
Riccia fluitans is a high maintenance plant due to its rapid growth and no root structure. When left floating close to the light source it can easily double in size within five days time. When submerged, the growth rate is slightly slower, but still requires weekly trimming to shape it into a nice manageable mound, or foreground. If left to overgrow, pieces of Riccia fluitans do have a tendency to break away from the main mass, and wind up in other plants or around a filter’s intake.
Close-up Riccia fluitans
Riccia fluitans forms thick clusters of bright green threads. If you refrain from pruning, Riccia fluitans will grow into a sphere shaped clump with slightly flattened “poles”, quite similar to planet Earth. Small clumps of Riccia fluitans normally float at or just below the surface. As the plant grows bigger and heavier, it will gradually sink down into the water.
Riccia fluitans does not develop any real root system, but it can anchor itself to solid objects such as rocks and branches. Use a piece of string or a rubber band to attach your Riccia fluitans to begin with and remove the string/rubber band when the plant has anchored itself. In some cases, there will be no need to remove the thread because it will be completely covered in lush green.
Aquascapers submerge Riccia fluitans by securing it around rocks using thin hairnets or sewing thread. Wedged tightly between the rock and the hairnet/thread, the fine Riccia branches will grow in between the cracks, and form an interlaced bushy Riccia mound. Remember, Riccia has a tendency to grow to the shape of the item it is attached to. For a flat foreground appearance, attached Riccia to a thin slate rock or heavy wire mesh. For a more hilly effect, use various sized round rocks.
Heavy wire mesh for a flat lawn effect
Well-grown riccia planted on heavy wire mesh
Anchoring riccia under thin net onto small rock
Riccia fluitans tied on pieces of wood
Riccia tied using fishing line on slate rock
Clusters of Riccia fluitans mounted on boulders
Trimming or thinning out Riccia is essential so that the lower portions of the plant will still see light and remain secured underneath the mesh. For trimming maintenance, it is best to turn off the filter first, and then trim with scissors. Net all floating bits before turning the filter back on.
Riccia looks stunning as the sole plant in a planted aquarium, or it can be easily paired with other foreground species such as Hemianthus callitrichoides (HC), or Eleocharis parvula (dwarf hairgrass) to complete an Iwagumi style layout.
For those who may grow tired of maintaining Riccia masses, there is a dwarf variety of Riccia Fluitans which contains smaller branches, and has a slower growth rate. The aquascaping possibilities with Riccia fluitans are limitless.
Riccia fluitans in the aquarium
As mentioned earlier, Riccia fluitans is a truly versatile plant that can be utilized in a wide range of ways on the aquarium. Even though it is a floating plant, it can be grown completely submerged. You can let it float free or anchor it to rocks and driftwood to make an “aquarium lawn”. You can let it grow over larger rocks and/or ledges in the aquarium to create a green, hilly landscape.
Riccia fluitans care
Caring for Riccia fluitans is not an arduous task, unless you wish to spend a lot of time pruning into specific shapes. Riccia fluitans is found in a rich assortment of various habitats in many different parts of the wild, and can tolerate a water temperature from 15 to 30 degrees C. This means that you can keep it with a wide range of different fish species. The water hardness can be medium soft to really hard and the pH-value can vary from 6.0 to 8.0.