Pygmy chain sword (Helanthium tenellum)

Overview

The pygmy chain sword, still sold as Echinodorus tenellus although it is now classified as Helanthium tenellum, is the miniature of the Amazon sword family. It forms small rosettes of thin, grass-like leaves 2-4 inches long that can blush reddish under strong light.

It grows in marshes and along shorelines in both North and South America, submersed or emersed. In the aquarium it spreads by runners into a natural-looking lawn. It is a classic plant, used for decades in Dutch-style and community tanks, and suits hobbyists with a little fertilizing experience.

Care and tank setup

Pygmy chain sword is easier than high-tech carpeting plants, but it needs enough light and nutrients in the substrate to spread.

• Light: medium. In low light the leaves stretch and growth stalls; with more light it stays short and may turn reddish.
• CO2: optional, but it makes the lawn noticeably denser.
• Substrate: fine and nutrient-rich, or fine gravel with root tabs. It is a heavy root feeder.
• Planting: separate the rosettes and plant them about 1 inch apart, with the crown level with the substrate.
• Placement: foreground, in open, unshaded areas.

After planting it may take a few weeks to adjust to underwater life and drop its emersed leaves; that's normal. It dislikes coarse gravel and iron deficiency, which shows up as yellow leaves. Keep digging fish away while it settles in.

Fertilizing and trimming

Push root tabs near the rosettes every 2-3 months and dose a liquid fertilizer with iron. It doesn't need trimming as such: remove old leaves at the base and keep runners in check when they invade other areas. If the rosettes crowd together and start growing upward, thin out the lawn by pulling some plants so it stays low.

Propagation

It propagates by runners: each rosette sends out creeping stems that form new plantlets an inch or so away. Once they have roots and several leaves, snip the runner and replant them. When established, it spreads fairly quickly. Emersed plants may flower, but in the aquarium reproduction is vegetative.

Recommended equipment

What you need to keep the Pygmy chain sword (Helanthium tenellum) healthy, checked against Amazon stock.