Pygmy chain sword

Overview

The pygmy chain sword (Helanthium tenellum, formerly Echinodorus tenellus) is one of the easiest carpeting plants — a small, grassy sword that spreads by runners into a low foreground lawn, and does it without CO2. That makes it a rare thing: a genuine carpet within reach of low-tech, beginner tanks. Some forms flush reddish-bronze under strong light, but even plain green it’s a lush, natural-looking ground cover.

Planting & placement

Plant small clumps or single plants into the substrate, spaced a few centimetres apart across the foreground — the gaps fill in as runners spread. Bury the roots and keep the crown at the surface. As a root feeder it appreciates a nutrient soil or root tabs beneath the carpet. See how to plant aquarium plants for planting small plants and aquascaping for beginners for building a foreground.

Light, CO2 & ferts

Medium light keeps it low and carpeting; too little and it stretches up to reach the lamp. It needs no CO2, though adding it speeds the spread and tightens the lawn. A nutrient substrate or root tabs feed the roots, topped up with a light liquid fertilizer. Our best light for a planted tank guide covers intensity for a good carpet.

Propagation & problems

It propagates by runners all on its own, chaining new plantlets across the substrate; lift and replant runners to speed coverage or thin a crowded carpet. The main issue is stretching in low light — raise the lamp to keep it short. In a very bright tank, algae can settle among older leaves, so pair it with grazers like cherry shrimp and nerite snails and keep the carpet trimmed and healthy. It sits well in front of taller midground plants such as Cryptocoryne becketti, and alongside other easy carpets like Micro sword and dwarf sagittaria.