Pygmy Chain Sword

Anyone who has been in the hobby a while knows this plant as Echinodorus tenellus. It is now filed under Helanthium tenellum, though the old name is still in use. It is the smallest of the runner-forming sword plants and a variable one. The form usually in trade has very narrow submersed leaves, about 1.5 mm wide and 6 to 10 cm long, sometimes longer, in medium to olive green or even reddish. A second form from North America, sold as parvulum, has lighter leaves around 2 mm wide, and is rarely cultivated now.

Where it comes from is less settled than the care sheet. The trade variety originates from the American tropics, possibly Brazil.

Runners are the whole story with a carpet plant, and this one sends them out quickly. Growth is fast, propagation is by runners, and the result is a grass-like lawn. It rates the plant medium difficulty. The published optimum is 18 to 28 °C with pH 5 to 7.5, carbonate hardness 0 to 14 dKH and medium to high light. The tolerance band is unusually wide, 10 at the bottom and 35 at the top.

Its leaves grow to about 10 cm. Its CO2 range is 20 to 40 mg/l.