Subwassertang is an exceptional low light aquarium plant that is prominent in shrimp tanks. This attractive plant is known by the common names Süsswassertang, Loma fern, Round Pellia, and False Round Pellia.
Subwassertang is fairly hardy regardless of its small size and delicate appearance, its growth is slow but these changes as soon as it acclimatizes to the new environment.
Interesting fact: It is closely related to the species Lomariopsis lineata according to DNA analysis. However, Subwassertang has not been named as a distinct species yet and it cannot be expressly regarded as Lomariopsis lineata either. Basically, this plant does not even have a scientific name.
Keep reading for more information on Subwassertang; these include the origin, how to cultivate and care for it in planted tanks.
Quick Notes about Subwassertang
|Süsswassertang, Süßwassertang, Loma fern, Round Pellia, and False Round Pellia
|Does not have (genus Lomariopsis)
|Tank Size (minimum)
|2.5 gallons (10 liters)
|Low to moderate
|6.0 – 8.0
|0 – 8
|20 – 24 °C (68 – 75°F)
|Any / floater
|Low to moderate
|Placement in Tank
|up to 20 cm (8 inches or more)
|Not needed – Low
|Not needed – Low
How to Pronounce Subwassertang
Subwassertang (Süßwassertang) was coined from the German words süßwasser which stands for “freshwater” and tang which means “sea weed”.
The name Subwassertang is erroneously spelt instead of Süßwassertang, in this case the letter ”ß” is a German grapheme called Eszett which represents an ‘s’ phoneme in German orthography, Süßwassertang is therefore pronounced as Süsswassertang.
Double SS is not a Z, as a Z in German is pronounced TZ like blitz (not the English Z).
Origin of Subwassertang
Subwassertang is a popular aquarium plant, it has been long considered to be a liverwort due to its ribbon-like thallus.
In actual sense, Subwassertang is not algae, moss or liverwort, rather it is the prothallium or gametophyte of a fern.
This plant was introduced to the aquarium hobby by Christel Kasselman after its discovery in the early 2000s, Kasselman propagated it and gave out some to other aquarists, and it continued to spread among hobbyists worldwide. How the plant made its way into her aquarium is unknown.
Species: Lomariopsis sp. (the closest relative)
Habitat of Subwassertang
Even biologists acknowledge the fact that they do not know much about this species, and to date, they are unaware of any record in which the gametophytes of Lomariopsis lineata have been observed naturally growing in aquatic environments.
They presume that Subwassertang and Lomariopsis lineata are native to tropical parts of Asia and Africa where it grows on trees and hardscapes by attaching on it firmly with its numerous rhizoids. Subwassertang exhibits an epiphytic behavior, it also grows on rocks in periodically dry rivers.
Interesting fact: According to the study, because there was only one known introduction by Kasselman into the aquatic trade, it can be reasonably assumed that all of the plants currently being sold are exact clones of each other and have reproduced entirely by continuous meristematic growth.
Description of Subwassertang
This fern gametophyte never develops further and continues to grow and replicate staying as a gametophyte. It has a striking resemblance with the liverwort species Monosolenium tenerum which is erroneously called Pellia.
Subwassertang consists of a group of branching ribbon-shaped thallus. This thallus is thin like a membrane (only one layer of cells thick), there is no midrib. Also present are broad round lobes, the tip is never truncate, and beneath these thallii are rhizoids (hairlike organs that serve as roots and helps in anchoring the plant to hardscapes or decoration.
The rhizoids are often grouped and located at irregular distances on the underside and also near the margin of the thallus.
The distinguishing factor between Subwassertang and Monosolenium tenerum is that the thallus of Subwassertang is more transparent and of a darker green shade, it is also more flexible and less fragile than the later.
Tank Requirements and Water Parameters
Subwassertang is an ideal choice for both nano and large tanks. The minimum tank size for growing this plant is 2.5 gallons (10 liters).
Water type, Temperature, Hardness, and pH:
Temperature: It grows best in the temperature range of 68 °F to 75 °F (20 – 24 °C). In nature, it can thrive in cold temperatures.
pH: The plant will appreciate the pH between 6.0 – 8.0.
Water Hardness: Even though Subwassertang can tolerate a wide range of water hardness. It still prefers soft water, this could be in the range of 0 – 8 dGH.
Ideally, medium lighting is required, this will result in more yield and an increase in its growth rate. Subwassertang will also grow well in low lighting conditions, however it comes at an expense which is a slightly slower growth and dull appearance. Nonetheless, even under low light bottom leaves will be OK.
Note: There are also many reports that Subwassertang does not like high light in the tanks, it can melt away.
Subwassertang prefers a medium flow rate, a high water flow will make them float around in the tank and this might even make some parts of the plant to break off.
CO2 and Fertilization:
CO2 injection is not necessary for this plant’s growth although it can increase the growth rate a little bit.
Subwassertang will do just fine without the application of liquid carbon and fertilizers.
Important: If you plan to add Subwassertang in a shrimp tank or high-tech planted tank with CO2 and regular fertilization, 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 Subwassertang
Unlike most aquarium plants, Subwassertang doesn’t need much attention and care. Some aquarists do not even bother to properly plant/attach it to anything. They just throw it in the tank. Subwassertang will find a spot it likes and grows.
One of the major reasons why it is in my good books is because it can grow successfully without CO2 and fertilizer application. Hence, it is a perfect choice for shrimp tanks and low-tech planted tanks.
Most of the needed care is centered on carrying out routine partial water changes in order to balance the water parameters and maintain good water quality.
Pruning is only required after a long while, Subwassertang is a slow-growing plant but once established you will witness explosive growth in the tank. When the clumps are getting too dense or growing out of shape, you should prune it to keep it compact.
Planting and Propagation of Subwassertang
Planting Subwassertang is quite easy, and the interesting part is that it can take various artistic shapes and forms for an increased visual appeal.
You can allow Subwassertang to be free-floating in the tank till it settles on a spot. Apart from that, you can get a bit creative and attach it to decorations like driftwood, rocks, and pipes.
Subwassertang sticks to surfaces like a small piece of wood with ease, all you need to do is to spread a little bit of Subwassertang on the piece of wood, tie the clumps with a black thread or fishing line all around it a couple of times, afterward, pass the thread through the loops to overlap all the area before you finally knot it. Attach divided pieces of Subwassertang to driftwood (shaped like a tree) to form a Süßwasser tree.
You can also stick small portions of Subwassertang into a crevice of wood or rock, this will make it look like it just happened to grow there naturally.
Some hobbyists tie theirs to a mat/pad slate and place them on the substrate to form carpets, they find it easier to grow it that way than just placing it directly on gravel to root.
Another option is to attach clumps of Subwassertang to an acrylic ledge which is then held on the aquarium glass by suction cups. This will create an artistic illusion of plants floating in your aquarium.
Subwassertang propagates by division. To propagate Subwassertang in tanks, simply break off small portions of it, attach it to a hardscape and it will grow into a whole new plant.
Make sure to disinfect Subwassertang in a bleach or salt dip before placing it into the tank. This helps to eliminate the chances of unwanted pests and snails being introduced into your tank.
Benefits of Subwassertang
Aesthetics: Subwassertang can be used to create artistic effects that complement the visuals of an aquarium. This plant can be made to take various forms like a tree, carpet, ball, and a wall. It offers similar flexibility that is achieved with java moss. You can use it as a foreground plant if you trim it down really well.
Frankly saying, it looks way better than what the pictures or videos show.
Oxygenation: Helps in oxygenation by actively promoting the availability of oxygen-rich water.
Hiding place for fish, fry, and shrimp: The dense clumps of Subwassertang provides hiding spots for shrimp and helps them keep safe from predators. It also serves as a spawning and/or breeding place for egg scatterers.
Foraging place: Subwassertang provides a natural and convenient foraging ground for baby shrimp and snails. Its structure acts as a buffet of biofilm, which is an ideal first food for newly hatched fry and shrimplets.
Alternative to mosses: Some people say that they cannot grow mosses in their tanks. If it is your cases, give Subwassertang a shot.
Removal of excess nutrients: Subwassertang is beneficial in neutralizing toxins and heavy metals in the tank. However, in the beginning, it grows pretty slow, therefore, the consumption rate can be pretty low as well.
Common Problems of Subwassertang
Growth rate: It is one of those plants that can take a long time to adapt to new parameters. In many cases, it takes weeks and even months for Subwassertang to start growing. However, it grows pretty quickly once it is well established and gets the best conditions it desires in the tank.
Melting: The plants will gradually melt or smother if the water parameters are unstable. Therefore, you should avoid making drastic changes to the aquarium, always endeavor to maintain low – medium lighting, and ensure that the tank water is clean.
Hard to attach: Subwassertang does not have roots. It uses small rhizoids in anchoring to hardscapes or decoration. Tying it loosely seems to be the best choice. If you tie it too tight it crunches the plant and it can die right where you want it to attach.
Algae: Subwassertang is susceptible to algae growth especially hair algae in hard water conditions, another factor that encourages this is the availability of intense lighting or prolonged photoperiods which is not even required for this species.
Sensitive to Seachem Excel: Even though Seachem Excel (link to Amazon) does not kill Subwassertang, it can slow down the growth rate.
Disinfection: Subwassertang is a hardy plant but because of its tin structure, it does not react to dips very well. It often starts turning brown. So, be careful about that.
Subwassertang and Tankmates
Suggested compatible tankmates include:
- Peaceful Fish. It would be a nice idea to keep this plant in the company of fish that won’t harm it. Good examples include Otocinclus Catfish, Pygmy Cory Catfish, Neon tetras, Guppy, Cherry Barb, Green Swordtails, Rasboras, Red, or blue wagtail platy, etc.
- Shrimp. In addition, shrimp species – all varieties of Neocaridina species (Red Cherry Shrimp, Blue Velvet Shrimp, Black Rose, Snowball shrimp, Orange Sakura, Green Jade, Rili Shrimp, etc) or Caridina species (for example, Crystal Red Shrimp, Caridina cf. babaulti, Blue Tiger Shrimp, etc.), Amano shrimp, Ghost shrimp, Bamboo shrimp, Vampire shrimp, Basically, you can keep any shrimp species with it. They will love it!
- Snails (for example, Ramshorn snails, Nerite snails, Malaysian Trumpet snails, Japanese trapdoor snails, Mystery snails,). Be careful with snails that can harm or try to devour the plant. Check out the list of freshwater snails here.
You should avoid hostile, aggressive diggers and voracious plant-eaters, that will waste no time in tearing up the plants and fighting other fish in the tank. Fish species like Silver Dollar, Oscars, Cichlids.
Do not keep Dwarf Sagittaria with crayfish or crabs. It is a well-known fact that these invertebrates are plant destructive (read my introduction to crayfish care). They will eat and uproot everything in the tank. Therefore, the best choice will be to have floater plants in their tanks.
Subwassertang is pretty rare, hence it may be a bit difficult finding it in offline pet stores. However, it is a different ball game online as one can easily find it available in online stores through a simple Google search. Just make sure to purchase healthy portions and you will be rewarded with a lush and robust growth.
Finally, don’t forget to disinfect the plant regardless of the vendor’s claims, you wouldn’t want snails creeping into your tanks uninvited.
I always recommend to quarantine or sterilize any plant first (using bleach to get rid of parasites and treating them with alum to eliminate snails) before putting it into your tank! The point is that:
- They can have parasites, pests like snails, or even predators (dragonfly, damsefly nymphs, etc.).
- They can be treated with chemicals (pesticide) to remove parasites, snails, etc. However, these chemicals are extremely poisonous to fish, shrimp, and other invertebrates.
However, Subwassertang is one sell thick; therefore, it is very sensitive to treatments. Having such a thin cell wall may cause it to burn and die quicker. That is why you have to at least dilute it.
At the same time, a less potent dip may not kill the snails and other parasites. In my opinion, putting Subwassertang in a quarantine tank for a few weeks is the best way to treat it.
To find out more, read my articles:
Subwassertang is a hardy plant and a close substitute for the renowned Java moss. The lush green cushions and beautiful form of Subwassertang make it an interesting addition to planted tanks especially shrimp tanks.
You will often notice shrimp hiding and roaming freely on its dense green foliage. It provides a lot of surface area for shrimp to graze and get on with the rest of their activities.