Heteranthera zosterifolia, commonly known as the Stargrass, is a nice-looking aquatic stem plant that became popular due to its bushy and lovely green texture after it was used in Takashi Amano’s aquascapes.
Although many sources recommend the Stargrass as beginner friendly, I would disagree with them.
On the one hand, Heteranthera zosterifolia is a relatively versatile plant and can grow in any substrate.
On the other hand, its fragile structure and extremely fast growth rate will require constant maintenance. In addition, it needs lots of light and soft water to keep its bushy appearance.
If you are considering adding Heteranthera zosterifolia to your tank, then you will definitely find this article helpful. This article provides a lot of information about the Stargrass; these include how to plant and care for it in an aquarium.
Quick Notes about Heteranthera Zosterifolia
|Common Name||Heteranthera zosterifolia|
|Lighting||Moderate to high|
|Optimal pH||5.5 – 7.5|
|Optimal GH||1 – 6|
|Optimal Temperature||68 – 79 °F (20 – 26 °C)|
|Can Be Grown Emersed
|Growth Rate||Very fast|
|Placement in Tank
|Size||10 – 20 inches (20 – 50 cm)|
Etymology of Heteranthera Zosterifolia
The name Heteranthera has Greek roots and comes from the combination of the words ‘Heteros’, meaning different, and ‘Antheros’, meaning anther from unequal anthers of most species.
The species name, Zosterifolia is from the Latin ‘Zostera’, meaning sea grass, and ‘Folium’ referring to a leaf.
Distribution of Heteranthera Zosterifolia
Heteranthera zosterifolia is native to Brazil (states of Tocantins, Rondônia, Bahia, Rio Grande do Norte, Mato Grosso, Mato Grosso do Sul, Goiás, Distrito Federal, Minas Gerais, São Paulo, Rio de Janeiro, Paraná, Santa Catarina, and Rio Grande do Sul), Bolivia (El Chaco boliviano), northeastern Argentina (the provinces of Jumps and Missions), Uruguay, and Paraguay (Sierra de Amambay), with disjunctive populations in Colombia.
Note: Many aquatic plants from northern South America are misidentified as Heteranthera zosteraefolia, but are actually Eichhornia diversifolia.
Habitat of Heteranthera Zosterifolia
Heteranthera zosterifolia grows in slow and calm waters of streams and rivers.
The Stargrass is a mostly submersed plant. However, it sometimes may develop emersed.
In the wild, this plant generally grows in dense colonies which may result in the development of floating (but still rooted) mats.
Description of Heteranthera Zosterifolia
Distinguishing characteristics of the Stargrass:
- Plant size: This plant features a height of 10 – 20 inches (20 – 50 cm) with dense, thin, and narrow leaves that are about 2 inches (5 cm) long and 0.04 inches (5 mm) wide.
- Structure: Sessile leaves are produced from an elongated vegetative stem. The leaves are linear to oblanceolate, clasping at the base, and acuminate at the apex. Leaf length is not highly variable. At the end of the stem, the leaves grow most densely and luxuriantly and resemble a star, which is why this plant is also called the Stargrass.
- Growth form. Heteranthera zosterifolia can be grown emersed or submersed. When grown submersed, the vegetative stem of Heteranthera zosterifolia has elongated internodes. In the emersed state, the stem trails along the ground without rooting.
- Color: The leaves are usually light green on the upper side and on the underside.
- Roots: The roots are thin, white, and weakly developed.
Heteranthera zosterifolia is a flowering plant. It forms lovely blue or white flowers only if its peduncles grow above the surface. The length of time flowers are open is not known. Flowering stems have either sessile or petiolate leaves.
Tank Requirements and Water Parameters
Heteranthera zosterifolia can survive in a relatively wide range of water parameters. The problem though, it will look leggy and truly ugly if not grown in optimal conditions.
Its ideal conditions include high light, CO2, nutrient demands, and soft water. Obviously, it can be really hard for beginners to fulfill.
Heteranthera zosterifolia requires a lot of space because of its growth potential.
Therefore, the recommended tank size for growing the Stargrass is a minimum of 30 gallons (~120 liters). The bigger the better.
Also, keep in mind that long tanks are better than tall tanks for this plant. In long tanks, the plant will get more lighting and thus become bushy. In tall tanks (more than 15 inches deep or 40 cm), the Stargrass will start growing upward and lose its form.
Water type, Temperature, Hardness, and pH:
Temperature: Heteranthera zosterifolia grows best in the temperature range of 68 °F to 79 °F (20 – 26 °C). In nature, it does not like cold temperatures. In lower temperatures, the growth rate slows down significantly.
pH: This plant prefers slightly acidic water in the range of 5.5 – 7.5 pH.
Note: The pH level of the water affects the plant nutrient uptake and therefore it is a significant factor for plant growth. Be sure to monitor the pH level regularly with an accurate pH testing kit.
Hardness: Soft water is required for this plant to grow comfortably. I need to repeat it again – soft water is important! It is highly recommended to provide hardness levels between 1 – 6 GH.
Keeping Heteranthera zosterifolia in alkaline and/or hard water can lead to the destruction (melting) of the plant.
Heteranthera zosterifolia will need good lighting to maintain its robust appearance. Under high lighting, it often trails along the ground (almost like carpeting plants) with short internodes.
Bright illumination is required to witness the full growth potential of this plant. Therefore, you should provide at least medium-high lighting (30-50 PAR) using an efficient lighting system.
When exposed to low lighting conditions, the leaves become smaller, the plant grows thin and leggy at best. However, in most cases, even when shaded, it will simply melt in the tank.
In nature, Heteranthera zosterifolia grows primarily in loose substrates and does not root very deeply. It is not usual to find it on cobble, sand, or even rock ledges.
Basically, the substrate does not matter, it can grow in any substrate because this plant absorbs nutrients from the water column.
This plant does not like high flow. In its natural habitat, this plant is found in slow-flowing rivers and streams.
Too much flow may make it melt in days.
CO2 and Fertilization:
CO2: CO2 supplementation is highly recommended for Heteranthera zosterifolia, it is very difficult to grow this plant without CO2.
Without CO2 the Stargrass will look flaccid, leggy, and stretched out.
Important: You need to understand that high-light demanding plants must be balanced in terms of CO2, and nutrients. It is never recommended to use strong lighting without CO2 injections, in simple words, you will have algae problems. A lot!
Fertilization: Heteranthera zosterifolia is a very fast-growing plant. Therefore, it needs nutrients. Macro and micronutrients will help to sustain healthy growth and ensure that the plants maintain the best coloration.
Regular dosing of liquid plant fertilizers (2-3 times a week) is required.
Note: If you keep shrimp in the tank with Heteranthera zosterifolia, 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 Heteranthera Zosterifolia
Do not allow the plant to reach the surface. You will get a big tangled mass.
Start trimming it when there are 4-6 (10-15 cm) inches to the surface of the water. You can safely shorten it by half. Do not worry, it will grow back very quickly.
Planting Heteranthera Zosterifolia
In aquascaping, Heteranthera zosterifolia is generally used to design the background of the tank.
You need to place the specimens into a substrate having a thickness of 2 – 3 inches (5 – 7 cm) to prevent difficulty in rooting. This plant does not have a strong root system; it serves mainly for plant attachment.
It will be better to maintain a spacing of about 3 – 4 inches (7 – 10 cm) apart from each other. This way it will reduce the competition at the early stage and you will not get an entangled mess later.
- Avoid putting Heteranthera zosterifolia too close to the glass. Once it starts to grow bushy, the glass will limit its growth form.
- Do not glue Heteranthera zosterifolia onto driftwood or anything else. This plant will not survive.
- Although this plant can grow emersed, it is not good for the Dry start method.
Propagation of Heteranthera Zosterifolia
The best way to reproduce it is clonal micropropagation. Simply cut off the stems (that have 4 – 6 leaves) and plant them.
Stems from regular trimmings can be used for this purpose. You can also remove the leggy stems and replace them with new ones.
Problems Associated With Heteranthera Zosterifolia
Melting: Unfortunately, there are many reasons why Heteranthera zosterifolia can melt all of the sudden.
- Sudden changes in water parameters can cause it to melt.
- Too hard and/or alkaline pH.
- Low lighting, overshadowing, and short photoperiod.
- Not enough fertilization and CO2.
Fragile: Heteranthera zosterifolia has fragile stem. It is very easy to break during maintenance.
Solution: Just be extra careful when handling this plant.
Discoloration: Changes in color may be triggered by a deficiency in nitrogen (NO3) and phosphates). Heteranthera zosterifolia may also change from bright green into a darker hue without enough phosphorous (PO4). Black dots mean that it requires iron.
Solution: Regular feeding. Use liquid fertilizers periodically. Going forward, always test the tank water and ensure it holds ample nutrients to promote optimal health and development of the plants.
Leggy bottom leaves: When Heteranthera zosterifolia gets really large the lower leaves may die back. Top leaves start blocking the light for the lower leaves.
Solution: Prune the plant. Check the lighting and provide CO2. These are usually the main reasons.
Fast growth/ Overgrowth: Under high lighting and CO2, Heteranthera zosterifolia can grow like a weed. It can fill up the tank within weeks. So, it will require a lot of clipping.
Solution: The plant will require regular stem trimmings to prevent it from overtaking the whole tank.
Ugly aerial roots: Heteranthera zosterifolia tends to grow some long aerial roots. There are not many of them but I find them ugly anyway.
- How to Spot Nutrient Deficiencies in Aquatic Plants
- Everything about Nitrates in Planted Tanks
- Phosphates in Freshwater Tanks
Benefits of Heteranthera Zosterifolia
Oxygenation: Helps to generate oxygen in the tank water. Heteranthera zosterifolia has a distinct feature which is the production of small pearls or bubbles of oxygen that stays on top of the plant, this adds a very lively aspect to the plant.
Hiding place: Serves as cover and shade for inverts and small fish. The structure of this plant forms small tunnels that are important to the early life stages of animals as a refuge from predators and as nursery areas.
Foraging place: Acts as a buffet of biofilm, which is an ideal first food for newly hatched fry and shrimplets.
Heteranthera Zosterifolia and Compatible Tankmates
Heteranthera zosterifolia should be kept with docile freshwater fish and inverts.
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.
Inverts are not left out. Considering the fact that Heteranthera zosterifolia 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 Heteranthera zosterifolia 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.
Heteranthera zosterifolia 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.
Stargrass looks really nice when grown like a bush.
The main problem though is that Heteranthera zosterifolia is not easy to maintain and care for. This plant requires soft and acidic water, CO2, regular fertilization, and strong lighting. Otherwise, it will melt or become leggy.
In addition, because of its fast growth rate, you should be ready to trim it very often.
Therefore, it is more suitable for experienced aquarists due to its specific demands to grow healthily and maintain the best coloration in a freshwater tank.
- Pavlova, Anna A., and Mikhail Yu Cherednichenko. “In vitro Cultivation of Aquatic Plant Heteranthera zosterifolia Mart.” (2017).
- Pellegrini, Marco Octávio de Oliveira, and Julia Cristina Guarnier. “Flora of Espírito Santo: Pontederiaceae.” Rodriguésia 73 (2022).
- Horn, Charles Norman. A SYSTEMATIC REVISION OF THE GENUS HETERANTHERA (SENSU LATO; PONTEDERIACEAE)(ECOLOGY, DISTRIBUTION). The University of Alabama, 1985.
- Rodriguez, Estela Elizabeth, Alberto Carlos Slanis, and Pablo Gilberto Aceñolaza. “Nuevas adiciones a la flora de la provincia de Entre Ríos (Argentina).” (2013).
- Simpson, Michael G., and Darren H. Burton. “Systematic floral anatomy of Pontederiaceae.” Aliso: A Journal of Systematic and Floristic Botany 22, no. 1 (2006): 499-519.