Blyxa Japonica is an attractive aquatic stem plant that is famous for its use in Dutch and Iwagumi aquascaping. It grows bushy and has a lovely green texture. Nonetheless, despite its popularity in aquascaping, this plant is not for beginners.
Actually, it always amazes me when some aquarists say that Blyxa Japonica is easy to care for and grows like a weed. Really? Why do they disregard the fact that a lot A LOT of people struggle with it?
The truth is that growing Blyxa Japonica can be very challenging because it is sensitive to temperature, light, CO2, and nutrition.
If you are considering adding Blyxa Japonica to your tank, then you will definitely find this article helpful. This article provides a lot of information including how to care for the plant in a home aquarium and what kind of potential problems you may have with Blyxa Japonica.
Quick Notes about Blyxa Japonica
| Common Name | Blyxa Japonica |
| Other Names | Bamboo plant or Blyxa |
| Scientific Name | Blyxa Japonica |
| Tank Size (minimum) | 10 gallons (~40 liters) |
| Difficulty | Medium to difficult |
| Lighting | Moderate to high |
| Optimal pH | 5.5 – 7.0 |
| Optimal hardness | Soft |
| Optimal temperature | 73 – 79°F (23 – 26°C) |
| Substrate | Needed (Nutrient-rich) |
| Can float: |
Yes |
| Can Be Grown Emersed |
No |
| Size | 4 – 6 inches (10 – 15 cm) |
| Growth Form |
Stem |
| Growth Rate | Moderate |
| Placement in Tank | Foreground / midground |
| Fertilizer |
Needed |
| CO2 | Needed |
| Propagation | Vegetative and by seeds |
Taxonomy of Blyxa Japonica
The Blyxa genus belongs to the family Hydrocharitaceae proposed in 1806.
In 1866, this plant species was first described as Hydrilla japonica by Dutch botanist Miquel Friedrich Anton Wilhelm.
After that, it was also called as Blyxa angustipetala, Enhydrias angustipetala, and Blyxa alternifolia until it was finally classified as Blyxa Japonica by German and Russian botanists Paul Friedrich August Ascherson, Robert Louis August Maximilian Gürke and Carl Johann Maximowicz in 1889.
Note: In the aquarium hobby, Blyxa Japonica was first introduced at the beginning of the 20th century. However, it was not that popular until Takashi Amano started using it in his works.
Habitat of Blyxa Japonica
Its native range is tropical and subtropical South and East Asia.
Nowadays Blyxa Japonica has become naturalized in India, Nepal, Meghalaya, Bangladesh, Thailand, Japan, China, Malaysia, Indonesia, Vietnam, Korea, New Guinea, Celebes, and in the rice fields of northern Italy.
It can be found in a variety of wet habitats from bogs and swamps (particularly in sago swamps) to lakes, pools, ponds and along margins of rivers, canals, ditches and slowly flowing irrigation channels.
Blyxa Japonica grows only submersed in water up to 8 inches (20 cm) deep. Although this plant prefers shallow water, it is still a fully aquatic plant and cannot be grown emersed.
Description of Blyxa Japonica
Blyxa Japonica is a green, low-growing stem plant that is suited for adorning different sections of medium and large tanks.
Note: Even though it might look like a rosette plant such as Dwarf hairgrass, Dwarf sagittaria, Cryptocoryne, etc., in reality, it is not. The point is that its stem is very short, especially in young plants.
This plant features a height of 4 – 6 inches (10 – 15 cm) with dense, thin, and narrow leaves that are about 3 – 4 inches (7 – 10 cm) long and 0.04 inches (5 mm) wide.
The internodes of Blyxa Japonica stems occasionally remain contracted and the leaves appear to be radical.
The leaves are sessile with a sheathing leaf base, light green, linear, serrated, and acute. They have a distinct midrib with very fine longitudinal veins and are spirally arranged.
Blyxa Japonica is a flowering plant. It forms lovely white flowers only if its peduncles grow above the surface. Nonetheless, its flowers are also highly autogamous. It means that the stamens dehisce and deposit pollen on the stigmas before the flowers are even fully open.
Difference between Blyxa Japonica and Blyxa Aubertii
- Blyxa Aubertii grows larger, darker, and can turn red.
- Blyxa Japonica is smaller, brighter green but can turn reddish or goldenish.
Blyxa auberti is also a rosette plant whereas Blyxa japonica is a stem plant.
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Tank Requirements and Water Parameters
Tank size:
The recommended tank size for growing the Blyxa Japonica is a minimum of 10 gallons (~40 L).
Although technically, the plant can be used sparingly in tanks with lesser capacity (nano tanks), I would not recommend doing it, because it will require stable water parameters and CO2 injections. Unfortunately, it is very hard to do in nano tanks.
Water type, Temperature, Hardness, and pH:
Temperature: The temperature where this plant is grown should be appropriately regulated. The ideal temperature range for growing Blyxa Japonica is 73 – 79°F (23 – 26°C), best growth is attained only in tanks with warm water.
This plant does not like cold water and melts easily.
pH: Be sure to monitor the pH of the aquarium water. Essentially, a pH level of 5.5 – 7.0 is appropriate for this species. Blyxa Japonica needs slightly acidic water.
Hardness: Soft water is required for Blyxa Japonica to grow comfortably. I need to repeat it again – soft water is essential! It is highly recommended to provide hardness levels between 1 – 5 GH.
Substrate:
Blyxa Japonica is a very heavy-root feeder plant. It requires a nutrient-rich substrate, preferably iron-rich clay or aquarium soil, to grow optimally.
The substrate should have a minimum depth of about 1 – 2 inches (2.5 – 5 cm). This gives the plant a suitable medium to attach its fine, delicate roots, and provides essential nutrients for its growth.
Sand or gravel are not recommended because they do not allow the plant to stay rooted firmly.
Some recommended soil substrates for this plant include (links to check the price on Amazon):
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Lighting:
To grow Blyxa Japonica successfully, you are required to provide moderate-high lighting using full-spectrum bulbs.
Note: This plant tends to stay smaller under high light and a little bit higher under moderate light.
The availability of intense lighting allows Blyxa Japonica to attain a reddish tint with more compact growth whereas low light triggers upward growth (the plant becomes leggy) which defies the purpose of cultivating the plant in the first place.
In addition, you are meant to maintain a photoperiod of up to 10-12 hours daily.
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CO2 and fertilization:
CO2: Is it possible to grow Blyxa Japonica without CO2? Technically, yes. The only problem is that its growth tends to be way slower, less bushy, and dense.
Therefore, I strongly believe that CO2 injection is a necessity as far as Blyxa Japonica is concerned. One can either use liquid carbon or (preferably) a pressurized CO2 system (20-30mg/l) to supply adequate doses of CO2 for the plants.
In addition, under high light, your tank must be balanced in terms of CO2 and nutrients. Otherwise, it will be covered with algae in no time.
Thus this plant needs stable levels of CO2 to stay healthy and grow densely. So, it’s better to use a pressurized CO2 system.
Fertilization: Here comes another beginner’s trap. Having just a nutrient-rich substrate is not enough!
The thing is that Blyxa Japonica is a versatile feeder as well. It absorbs nutrients through roots (substrate) and the water column from their leaves.
This plant requires regular dosing of liquid plant fertilizers (2-3 times a week) and root tabs (periodically). Macro and micronutrients will help to sustain healthy growth and ensure that the plants maintain the best coloration.
| Important: Blyxa Japonica needs iron (Fe) – 0.1, phosphates (Po4) – 0.4, and nitrates (NO3) – up to 5 mg/l. |
Note: If you keep shrimp in the tank with Blyxa Japonica, 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 Blyxa Japonica
Blyxa Japonica is a demanding and finicky plant, it is definitely not the easiest plant to maintain in the aquarium. This plant will struggle in a low-tech tank due to its strong need for CO2 supplementation.
| Many plant nurseries in Europe seem to have stopped selling them because they are difficult to grow.
Generally, Blyxa Japonica is considered to be a difficult plant to keep alive for long periods. In scientific literature, this plant is classified as an “annual’ or seasonal plant. |
Lighting is another major factor that determines how this plant will turn out. It is necessary to ensure the availability of high lighting for proper growth, low to moderate light will result in leggy growth and that should be avoided at all costs.
Avoid placing the plants in shaded areas during planting— this is to ensure it gets enough light that will enable them to achieve the much-desired bushy effect.
Furthermore, make sure to use root tabs and dose fertilizers rich in macronutrients (Nitrogen, Phosphorus, and Potassium) and micronutrients (Iron, Manganese, Boron, etc.) to encourage optimal growth and development of the plant.
During a routine cleaning, make sure to stir Blyxa Japonica gently to release debris, food particles, and detached stems to the surface, these can be siphoned afterward.
Lastly, make sure to perform regular water changes (25-30 % weekly) to maintain good water quality, and ensure that the water parameters are kept within the proper ranges.
Until it takes hold, Blyxa Japonica is not a fast-growing plant.
Generally, this plant will not require much of any maintenance pruning. It is not too invasive. However, removing the oldest leaves from the new sheets is always a good idea as these tend to die off.
Planting Blyxa Japonica
Blyxa Japonica is suitable for placement in the foreground and midground of planted tanks due to its small size and bushy appearance.
- To plant Blyxa Japonica, first, untie the bunch and divide it into several portions.
- Next, disinfect or quarantine the plantlets properly (if they are not grown in vitro).
- When you are done, place the individual stems into the enriched substrate, and maintain the adequate spacing of about 2 – 3 inches (5 – 8 cm) from each other to prevent overcrowding and minimize shading.
- Place the stems 1 inch (2.5 cm) deep into the aquarium substrate to prevent difficulty in rooting.
Note: Blyxa Japonica is known to be problematic when you first plant it in the tank. However, with time, the plant will develop extensive and long roots (4-6 inches or 10-15 cm). - Avoid putting Blyxa Japonica near tall plants that can shade them.
- Avoid putting Blyxa Japonica too close to the glass. Once it starts to grow bushy, the glass will limit its growth form.
Floating:
Few hobbyists use Blyxa Japonica as a floater in their planted tanks until it develops enough roots. In 2-3 weeks, it will have roots 1-2 inches (2.5-5 cm) long.
As I have already mentioned before, Blyxa Japonica is able to extract nutrients from both the substrate and the water column.
Propagation of Blyxa Japonica
Blyxa Japonica can propagate in two ways:
- By seeds. Its flowers produce viable seeds that are collected and placed in water.
- Vegetative. New stems will begin to branch off of the base of the main plant, it will sort of spread out slowly on its own and the plant will become even bushier. In aquariums, we need to take out the plant and cut it off with scissors. If the new plant does not have roots, you can leave it floating until they develop.
Important: Do not forget to inspect it carefully for decaying particles or just bad leaves.
Problems Associated With Growing Blyxa Japonica
Melting: Unfortunately, Blyxa Japonica is a finicky plant. There are many reasons why this plant can melt all of the sudden.
- Stable water parameters. Sudden changes (especially hardness and pH) can cause it to melt.
- Low lighting, overshadowing, and short photoperiod.
- Not enough fertilization.
- Inappropriate substrate.
Rest (dormancy) periods: Blyxa Japonica has rest periods where the growth rate almost stops.
Solution: Check the hardness in the first place. Providing enough nutrients and keeping it in optimal water parameters will shorten this period to a minimum. Just wait until the plant recovers. Eventually, it will start growing again.
Nutrient sensitive: Blyxa Japonica cannot survive without nutrition for a long time. It dies down due to a lack of nutrients.
Solution: Regular feeding.
Fragile: Blyxa Japonica has fragile leaves. It is very easy to break them during maintenance.
Solution: Just be extra careful when handling this plant.
Hard to plant: It can be really hard to plant Blyxa Japonica into the substrate since the young stems easily get damaged. Also, in the beginning, the stem usually does not have well-developed roots to stay in the substrate, therefore, it may float away.
Solution: Plant it in the substrate using a pair of aquarium tweezers. Place some pebbles or rocks around the stem of the plant. Be careful, the rocks should not damage the stem or roots of the plant.
Palatable: Blyxa Japonica has fin leaves that some snails and fish species may find delicious.
Solution: Do your research beforehand.
Leggy growth: The stems can get a yellow tint and stretch out.
Solution: Check your lighting.
Discoloration: Changes in color may be triggered by a deficiency in iron and phosphates that are required for optimal health and development.
Solution: Hence, it is recommended to dose liquid plant fertilizers in the aquarium water regularly to maintain a good supply of nutrients for your live plants.
New tanks: It was noticed that Blyxa Japonica does not grow well in new tank setups. It seems like it requires a certain bio-balance in the substrate.
Solution: Wait until the tank matures.
Floating: When Blyxa Japonica splits (propagates), some plants dislodge themselves from the substrate and float. Basically, over time it just gets too big to stay in one place.
Solution: Maintenance.
Related article:
- How to Spot Nutrient Deficiencies in Aquatic Plants
- Everything about Nitrates in Planted Tanks
- Phosphates in Freshwater Tanks
Benefits of Blyxa Japonica
Aquascape: Blyxa Japonica can be an excellent decorative addition to your tank.
No Overshadowing: This is a small plant. Thus, it will not choke other aquatic plants. In addition, Blyxa Japonica does not grow fast to become invasive.
Hiding place for fish, fry, and shrimp: Blyxa Japonica serves as great cover and shade for inverts, small frogs, and fish.
Foraging place: Acts as a buffet of biofilm, which is an ideal first food for newly hatched fry and shrimplets.
Prevents gas pockets: Blyxa Japonica has a well-developed root system that will help to break up anaerobic pockets in the substrate.
Note: Hydrogen sulfide pockets (H2S, the gas smells like rotten eggs) can be really dangerous to your fish or shrimp.
Blyxa Japonica and Compatible Tankmates
The delicate, fragile, and palatable nature of Blyxa Japonica makes it picky about suitable tankmates. The plant will survive in tanks with critters that won’t see its soft leaves as a snack. Compatible tankmates include:
Fish:
The plant is best kept with small, peaceful community fish such as Neon tetras, Killifish, Swordtails, White Mountain Minnows, Zebra Danio, Cherry Barb, Sunburst Platy, Endlers, Mollies, Otocinclus Catfish, Pygmy Cory Catfish, etc.
Shrimp:
Inverts are not left out. Considering the fact that Blyxa Japonica prefers slightly acidic water. Thus, you should consider species that prefer the same water parameters, for example, Crystal red shrimp, Blue bolt shrimp, Caridina cf. babaulti, etc.
Once again, ornamental snails should not be kept in a tank with low PH for a long time. It will negatively affect their shell. However, if your pH is close to 7.0, it is possible to keep almost any snail or dwarf shrimp you like. Examples, Japanese trapdoor snails, Ramshorn snails, Nerite snails, Malaysian Trumpet snails, Black Devil Snails, Asolene spixi, Rabbit Snails, etc.).
Avoid or Be Careful
Avoid fish species that may disturb the substrate near the plant or find Blyxa Japonica 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.
Blyxa Japonica 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.
In Conclusion
Blyxa Japonica is an impressive and fascinating aquatic stem plant. This species can be used to create various artistic effects in all kinds of aquascape because of its distinctive form and lively colors that clearly stand out.
The main problem though is that Blyxa Japonica is not easy to maintain and care for. This plant requires soft and acidic water, CO2, nutrient-rich substrate, regular fertilization, and strong lighting.
Therefore, it is more suitable for experienced aquarists due to the high demands and special care required for it to grow healthily and maintain the best coloration in a freshwater tank.
References:
- Mandal, Sujit Kumar. “Blyxa Japonica (Miquel) Maximovicz Ex Ascherson Et Gurke Var. Japonica (Hydrocharitaceae) and Najas Malesiana De Wilde (Najadaceae)-New Records for West Bengal.” Field notes 5, no. 11 (2016).
- Pagag, K., and S. K. Borthakur. “Rediscovery of Blyxa japonica (Miquel) Maximowicz ex Ascherson et Gürke-a hydrophyte from Lakhimpur district of Assam, India.”
- Verbatim text: Cook, C. D. K., and R. Lüönd. 1983. A revision of the genus Blyxa (Hydrocharitaceae). Aquatic Bot. 15: 1-52.