© Krzysztof Ziarnek, Kenraiz / CC BY-SA 4.0Pygmy chain sword (Helanthium tenellum)
Echinodorus tenellus, commonly sold under the trade name Pygmy Chain Sword, is a diminutive aquatic plant with thread-like leaves only about 1.5mm wide. Though its current scientific name is Helanthium tenellum, it's still most often labeled by the older name. It spreads sideways by sending out runners, making it a popular choice for creating a lush, grass-like carpet in the foreground of an aquarium. As a perennial, once established it keeps propagating through runners, continually producing new plantlets. Under strong lighting the leaves take on a reddish tinge, while a 'Green' form stays green even under strong light, giving keepers a choice depending on the look they want. Rated as beginner-friendly, it's an approachable species even for those just starting out with aquascaping.
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Apply as a growerPygmy chain sword (Helanthium tenellum) key facts
- Growing Difficulty
- Beginner-friendly
- Lifespan
- Perennial; keeps spreading by runners
- Size
- 5–10 cm tall as a lawn; leaves about 1.5 mm wide
- Temperature
- 18〜28℃
- Watering
- Needs a nutritious substrate; CO2 makes it denser
- Lighting
- Medium to high light gives a dense lawn; many forms redden in strong light.
- CO2 & Fertilizer
- CO2 improves growth and density; provide a nutritious substrate.
- Water Temperature & Quality
- Optimum 18–28°C in softish water (pH 5–7.5, KH 0–14°dH).
- Substrate & Attachment
- Split into small clumps and plant spaced out in the foreground substrate.
- Trimming & Propagation
- Spreads by runners bearing plantlets; thin by pulling out excess plantlets.
- Cautions
- Its runners spread readily, so remove any that invade other foreground plants. Never release plants into the wild.
About Pygmy chain sword (Helanthium tenellum)
Echinodorus tenellus (Pygmy Chain Sword) is a beginner-friendly foreground aquarium plant with 1.5mm-wide leaves that spread via runners into a 5-10cm carpet.
7 things to know before growing Pygmy chain sword (Helanthium tenellum)
1Light Changes Leaf Color
Strong lighting tends to bring out a reddish tint in the leaves. A 'Green' form that stays green even under strong light is also available, so you can choose based on the look you want.
2Spreads via Runners
This plant multiplies on its own by sending out runners across the substrate. Leave some space between plants when first planting, since it will naturally fill in the gaps over time.
3Watch for Melting After Planting
Stock that was grown emersed (above water) may lose its old leaves shortly after being planted underwater. Give it time to grow in new, fully aquatic leaves before judging how it's doing.
4Plant Shallow and Spaced Out
The fine roots take hold with just a light press into the substrate. Planting too deep can cause the plant to melt or die back, so keep it shallow and give each plant some room.
5Trim Back Overgrowth
Because it spreads continuously via runners, an untended patch can become so dense that light no longer reaches the lower leaves. Thinning and trimming periodically keeps the carpet healthy and even.
6Choosing Healthy Plants
Pick specimens with no discolored or melting leaves, ideally with a healthy plantlet already forming at the end of a runner. Plants with very few leaves may take longer to establish.
7A Fine, Nutrient Substrate Helps
A nutrient-rich, fine-grained aquarium soil makes it easier for the fine roots and runners to take hold and spread. Coarser substrates can make it harder for the roots to anchor.
Frequently asked questions about Pygmy chain sword (Helanthium tenellum)
- Q.Is this plant suitable for aquascaping beginners?
- A.Yes, it's generally considered beginner-friendly. It's hardy and spreads naturally via runners, making it approachable even if you've never kept aquatic plants before.
- Q.Why do the leaves turn red?
- A.Strong lighting causes the leaves to take on a reddish tint. A 'Green' form is also available that stays green even under strong light.
- Q.How big does it get?
- A.When grown as a carpet, it typically reaches about 5-10cm in height. The individual leaves are very narrow, only around 1.5mm wide.
- Q.How does it propagate?
- A.It spreads by sending out runners that produce new plantlets, gradually filling in outward. As a perennial, once established it keeps multiplying this way over time.
- Q.Do I need to add CO2?
- A.It's not strictly necessary, but supplementing CO2 tends to encourage more vigorous growth and runner production. It's also hardy enough to get by without added CO2.
Handy Growing Tools for Pygmy chain sword (Helanthium tenellum)
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