Monosolenium tenerum (previously known as Pellia endiviifolia) is a very controversial plant with an interesting history.
On the one hand, this is a very easy plant to grow because Monosolenium tenerum doesn’t require a substrate and can thrive in a wide range of water parameters. Therefore, it can be recommended for beginner aquarists.
On the other hand, its invasive nature and fragile structure require more maintenance if you do not want the Monosolenium tenerum to be in every corner of your tank. So, you need to understand the risks and place this plant only in tanks with specific setups.
In this article, I will be talking about everything you need to know about this plant; a detailed care guide, and how you can easily cultivate Monosolenium tenerum in your aquarium.
Quick Notes about Monosolenium tenerum
|Common Name||Monosolenium tenerum|
|Other Names||Pelia moss|
|Optimal Lighting||Moderate to high|
|Optimal pH||6.0 – 8.0|
|Optimal GH||2 – 16|
|Optimal Temperature||68 – 82 °F (20 – 28 °C)|
|Growth Rate||Moderate to fast|
|Placement in Tank
||Foreground and midground|
|Size||up to 20 cm (8 inches or more)|
|Leaf size||1 to 1.4 inches (or 2.5 to 3.5 cm)|
||Not needed – Low|
|CO2||Not needed – Low|
- Land colonization by plants started in the middle of Ordovician period (about 470 million years ago). Thalloid liverworts (together with hornworts and mosses) are considered to be one of the earliest diverging land plants of early land colonization. Therefore, the Monosolenium tenerum represents the oldest living land plants.
- In 1849, this plant was described by British botanist William Griffith. However, an unusual combination of characteristics of Monosolenium tenerum led to the situation where for many decades even other scientists believed that W. Griffith, had largely imagined it.
Etymology of Monosolenium Tenerum
The etymology of the Latin word ‘Monosolenium’ is unclear. Presumably, it is made of two parts: Mono (meaning ‘Alone’)+Solenium (derives from Solanum, meaning ‘Nightshade’).
The name Tenerum is also of Latin origin meaning ‘Soft, delicate, or tender’.
Thus, Monosolenium tenerum can be translated as a delicate plant that grows alone in the shadows.
Destribution of Monosolenium tenerum
Monosolenium tenerum has a very limited subtropical Asiatic distribution. It can be found from Northeast and Northeast India, southern China, and Taiwan to southern Japan. Nonetheless, even there this plant species is located in only a few isolated areas.
Note: As a result of accidental dispersal by humans, Monosolenium tenerum was also documented in Nepal.
Habitat of Monosolenium tenerum
In the wild, Monosolenium tenerum is found growing emersed in high-humidity habitats. Yes, as a matter of fact, this is not a fully aquatic plant. So far, there are no reports of it growing as a submerged aquatic plant in the wild.
Monosolenium tenerum is a semi-terrestrial liverwort that inhabits damp places growing on moist shaded soil along forest streams and rivers.
Description of Monosolenium tenerum
Monosolenium tenerum is a perennial plant* that comprises a thallus. In other words, technically, this plant does not have organized and distinct parts (such as leaves and stems).
*Note: A perennial plant is a plant that lives more than two years.
Monosolenium tenerum can be recognized by its relatively thin, dark green, and fork-like branched thalli.
The length of each thallus (so-called ‘Leaves’) generally ranges from 1 to 1.4 inches (or 2.5 to 3.5 cm) long and 0.2 – 0.3 inches (5 – 8 mm) broad. Each thallus has a thickened midrib and thinner semi-translucent wings with wavy margins.
They are smooth from the top with no air pores or reticulations. Beneath these thallii are numerous rhizoids (hairlike organs that serve as roots and help in anchoring the plant to hardscapes or decoration).
Difference between Monosolenium tenerum, Subwassertang, and Riccia Fluitans
- Subwassertang (aka Lomariopsis lineata).The distinguishing factor between Subwassertang and Monosolenium tenerum is that the thallus of Subwassertang is more transparent, thinner and of a darker green shade, it is also more flexible and less fragile than the latter.
Also, Subwassertang has no midrib and a rounder, irregular growth pattern. While Monosolenium tenerum has mostly uniform, pointed growth.
- Riccia fluitans (Crystalwort). Monosolenium tenerum looks like “Riccia on steroids”, it is simply larger and darker. Also, Crystalwort’s body consists of air pores that help the plant to float. Whereas Monosolenium tenerum does not have them, thus, the plant is heavier than water and sinks.
Tank Requirements and Water Parameters
Monosolenium tenerum is adaptable to a wide range of water parameters and tolerant to varying conditions, and that qualifies it as an excellent candidate for various kinds of aquarium setups.
Note: You can even grow it in a jar on your windowsill before putting it in the tank.
It all depends on your choice and purpose.
Monosolenium tenerum can fit in any type of vessel and tank regardless of the size. From plastic /glass containers, jars, vases to large tanks.
Nonetheless, you need to keep in mind 2 main factors:
- under optimal conditions, Monosolenium tenerum can grow like crazy and quickly overtake nano tanks,
- it can be hard to keep this plant in one place. So, if you think about putting this plant in your nicely aquascaped 30 gallon planted tank, – think again!
Therefore, the recommended tank size for growing this plant is a 10-gallon tank (~40 liters).
Water type, Temperature, Hardness, and pH:
Temperature: The optimal temperature for growing Monosolenium tenerum is between the range of 68 – 82 °F (20 – 28 °C). Despite its subtropical origin, Monosolenium tenerum can easily stay alive even under colder temperatures. For example, it can tolerate temperatures as low as 50 °F (10 °C).
pH: This hardy plant does not care much about pH levels, however, it will appreciate optimal pH values between 6.0 – 8.0.
Hardness: Monosolenium tenerum is a very adaptable plant, it can thrive in soft water to hard water with values of 2 – 16 GH.
Monosolenium tenerum needs moderate – high lighting to photosynthesize and grow optimally. Under lighting conditions, it will grow at a visibly fast rate and release a great deal of oxygen in the tank. Bright illumination causes more compact and bushier growth.
Ideally, the lights should be kept on for at least 8 hours daily.
Monosolenium tenerum is not the best plant for low-tech tanks. Yes, it will definitely grow there as well but low light will trigger upward growth with longer gaps between the thallus (leaves). In addition, under low light, leaves become thinner and darker.
Monosolenium tenerum does not require any substrate. This is primarily because this plant mainly extracts nutrients from the water column. So, do not try to shove it into the substrate.
Monosolenium tenerum can be attached to stones, rocks, driftwood, bogwood, or any type of decorations. Any chosen substrate will do just fine, this plant can attach and grow on most surfaces perfectly.
Monosolenium tenerum prefers still water. A high water flow may make the plant float around in the tank and this might even make some parts of the plant to break off.
CO2 and Fertilization:
CO2: CO2 supplementation is not a necessity. At the same time, its growth rate can be painstakingly slow without CO2 in submerged environments. Also, it will grow stringy.
Important: You need to understand that high-light demanding plants must be balanced in terms of CO2, nutrients, and lighting. This balance is extremely important. Otherwise, you will have algae everywhere.
Fertilization: Monosolenium tenerum will grow in freshwater aquaria without nutrient supplementation. However, the benefits of regular fertilizer application are immense — as it ensures the plant grows faster and overall healthier.
Many aquarists noticed that Monosolenium tenerum responds positively to a high level of phosphates (1.5 – 2 mg/l range) in the water. Therefore, I’d still say that periodical fertilization is recommended.
Important: If you keep shrimp in the tank with Monosolenium tenerum, I would highly recommend reading my articles:
- CO2 in a Planted Tank Guide
- CO2 in a Shrimp Tank
- How Copper Affects Dwarf Shrimp
- Shrimp Safe Plant Fertilizers
The point is that a high level of CO2 and Copper (most fertilizers contain copper) is extremely dangerous to the shrimp.
Care and Maintenance of Monosolenium Tenerum
- Difficulty: On the one hand, caring for Monosolenium tenerum is relatively easy. It is one of the few plants that can grow in tanks with extreme pH, temperature, and water hardness conditions.
On the other hand, its maintenance is very tricky. This plant is very delicate and easily breaks. As a result, it may spread everywhere and overstuff the tank.
In addition, its growth form largely depends on the CO2, nutrition, and lighting in the tank. Obviously, it will grow faster and bushier under optimal conditions. Unfortunately, I would not expect it in low-tech tanks. In low-tech tanks, this plant will be less decorative.
|Warning: It requires some knowledge to create balanced hi-tech planted tanks. Therefore, if you are new to this hobby then you need to learn more about CO2, fertilization (macro and micro nutrients), and lighting.
Unless you are going to keep it in a paludarium setup with free excess CO2. In this case, Monosolenium tenerum will be a very good choice.
- Placement: Monosolenium tenerum is a relatively versatile plant that can be used for foreground and midground plantings due to its size and bushy appearance.
- Growth rate: When grown emersed in high humidity conditions, the growth rate will be pretty fast. Whereas, if Monosolenium tenerum is submersed the growth rate will be slow to moderate.
Planting of Monosolenium Tenerum
Monosolenium tenerum is very easy to plant and it can take a wide variety of forms. Here are some of the ways in which you can plant Java moss in an aquarium:
You can simply throw it in the tank. Due to the fact that Monosolenium tenerum is heavier than water, it will find a spot it likes.
Although Monosolenium tenerum does not produce roots, its leaves have numerous rhizoids that serve as roots and help in anchoring the plant.
Attaching to Rock & Driftwood
There is no need to remove thread or fishing line, the plant will grow and cover it.
Wall, Ball, etc.
Take a plastic mesh and suction cups to hold Monosolenium tenerum against the tank walls. Next, fold the plastic mesh net in half, sustain the folded nets with the suction cups and then carefully stuff the plant inside each end to form a wall.
Monosolenium tenerum will grow through the mesh and soon cover all the spaces.
Propagation of Monosolenium Tenerum
The propagative means of Monosolenium tenerum is through division. This involves breaking off pieces from the plant bunch and attaching them to surfaces or hardscapes.
If you see that the plant grows too thickly (thalli are touching and overlapping one another), it is time to divide it. Actually, by doing so you will increase its growth rate.
Alternative Way of Growing Monosolenium Tenerum
Therefore, another way to plant and grow this plant is to use the Dry Start Method (or DSM).
The Dry Start Method still significantly boosts the development of the slow-growing plants, cycles the substrate, and removes any algae problems!
It makes this plant a great choice for paludarium setups as well.
Problems Associated With Growing Monosolenium Tenerum
Brittle structure: Monosolenium tenerum is pretty brittle and cannot withstand pressure. It is easy to damage it during maintenance. As a result, its particles scatter throughout the aquarium, growing where you don’t want them.
Solution: Be extremely careful while handling the plant.
Hard to plant: Monosolenium tenerum does not have a well-developed root system. It makes it really hard to plant. In addition, under optimal conditions, tiny oxygen bubbles will start to form on the leaf tips”. Therefore, if the plant is not attached, it may even float a bit, however, eventually, it will sink somewhere in your tank anyway.
Solution: Attach the plant to something.
Invasiveness: Every broken part of the plant starts to grow. So, in some cases, it will be extremely hard to get rid of this plant if needed.
Solution: Be extremely careful while handling the plant.
Leggy bottom leaves: When Monosolenium tenerum gets really large the lower portions may die back.
Solution: Check the lighting. This is usually the main reason.
Hard to trim: Monosolenium tenerum is very difficult to shape and hard to aquascape with. Because of its brittle structure, trimming is almost impossible. Trying to pick pieces from hidden sections of the tank can be challenging.
Solution: Provide optimal conditions so the plant will not grow tall.
Decaying: If something gets on the plant, it may start to rot in this place.
Solution: Keep your water clean. Regular maintenance.
Benefits of Monosolenium Tenerum
Versatility: Monosolenium tenerum is one of the plants that can grow emersed and submersed.
Replacement: This plant can be easily moved around especially, if it is attached to wood, rocks, etc.
Hiding place for fish, fry, and shrimp: Monosolenium tenerum will serve as a cover and hiding place for inverts and small fish. They love to play in it and pick on it.
Monosolenium Tenerum and Compatible Tankmates
Monosolenium tenerum should be kept only with dwarf shrimp and small freshwater fish that would mechanically be able to damage it. As I have mentioned many times before, it is a very delicate plant!
Avoid or Be Careful
Avoid fish species that may disturb the substrate near the plant (Plecos or Catfish) or find Monosolenium tenerum too palatable, e.g. Silver dollars, Bueno Aires tetras, Koi fish, Goldfish, Oscars, Rainbow, Jack Dempsey, Clown loaches, African Cichlids. These species can really cause problems in the planted tanks.
Monosolenium tenerum and most types of crayfish or freshwater crabs are not a good combination as well. These animals will cut, eat, and uproot everything in the tank. So, keep it in mind and do your research beforehand.
Monosolenium tenerum is a hardy and versatile plant. It can grow emersed and submersed. Thus, it can be a great addition to your aquarium or paludarium.
The main problem though is that Monosolenium tenerum is very fragile. When it breaks off, all these tiny chunks will spread around the tank and start growing there. Frankly saying, it can get quite annoying when you are aquascaping.
- Pradhan, Nirmala, David G. Long, and Sanu Devi Joshi. “Monosolenium tenerum Griff.(Marchantiopsida, Monosoleniaceae) in Nepal.” Cryptogamie Bryologie(2007).
- Yang, Bao-Yu. “The discovery of Monosolenium tenerum in Taiwan.” Taiwania11, no. 1 (1965): 29-34.