• Scientific name: Echinodorus tenellus
• Synonym: Alisma tenellum, E. parvulus
• Common name: Pygmy chain swordplant
• Family: Alismataceae
• Group: Aquarium plants
• Max height: 15 cm
• Distribution: Widespread in North, Central and South America
• Habitat: The banks of more or less large rivers
• Substrate: Fine washed gravel, sand
• Placement in aquarium: Foreground in groups
• Planting density: 6-7 plants for 10 cm²
• Lighting needs: Bright
• Temperature: 18-28°C
• pH: 6-8
• Hardness: 3-6 NK°

Description: In good conditions, this tiny Echinodorus species will spread and create a lawnlike appearance across the foreground of the aquarium. Provide medium-bright lighting, a fine substrate, and medium-soft water. When you buy them, many specimens exhibit the terrestrial leaf form, which is more oval shaped and on short stems. When placed underwater, the terrestrial form will lose all the existing leaves before growing new aquatic ones.

The smallest sword plant is one of the most popular and most decorative plants for the foreground. Under the right conditions, especially intense lighting, a dense and low "cushion" made of runners will form after only a short time. In aquariums over 50 cm in height, care has to be taken to ensure adequate lighting of the foreground because the delicate plants will otherwise quickly perish. Because of the delicate roots, a fine gravel or sand substrate is best. Echinodorus tenellus will prosper better in soft to medium-hard, weak acid water compared to a hard, alkaline environment. The temperature tolerance of between 18 and 28 °C (temporarily even higher or lower) is very high. Two kinds of Echinodorus tenellus are cultivated in aquariums. They differ in coloring, leaf length, and growth height. Whereas one form displays light green, short blades, as well as low growth in the aquarium, the other form develops medium to dark green, often brownish, considerably longer leaf blades, and a growth height of up to 5 cm. The "False Tenellus," occasionally commercially available, is in fact Lilaeopsis brasiliensis.