Among the carpetaceae, this plant found its way into my aquariums first. It’s been a few years since I collected a few cups of this smallest representative of echinodorus with quite a lot of effort. The condition of the plants was deplorable, the owner of the aquarium shop gave me the cups for a symbolic price saying, “This plant never worked out for us somehow…”
Not much time passed and I regularly supplied the unnamed aquarium shop with surplus of this “grass”.
Let’s get down to facts: to achieve good and compact growth, the plant needs to be sufficiently well lit. It has worked well for me to plant several plants in a single clump (3-5 plants): grasp them with tweezers and plant them deep enough in the substrate. In this way I plant the clumps 3-5 cm apart. The plant develops a fairly dense root system. The old plants gradually die off their lower leaves, new ones form and after a while the bare stem or a kind of tuber is visible on the old plants – so I recommend planting deep enough. A nutrient-rich, sufficiently sized bottom must also be provided – a substrate thickness of 5 cm or more is optimal.
With a good water supply of CO2 and normal fertiliser, growth is quite rapid. With the help of whisks, the plant spreads around the aquarium and the carpet thickens nicely. In time it will overgrow moss, monosolenium, cryptocorynes, etc. at my place. If we grow other carpet plants in the tank in addition to E. tenellus, after a while it will be necessary to cut back and remove new shoots that appear in unwanted places. Occasionally I am asked if it is possible to prune the plant – I have never done this and never had to. The growth is compact, reaching a height of 5-7 cm. Under intense light, some leaves have a pinkish to red tinge. If fertilised too heavily, the height of the plant can reach more than 10 cm, which is already an unwanted effect, especially when used in low aquariums.
I think that nowadays E. tenellus is a widely available and popular plant. It is one of the less demanding of the carpet plants. Its use is almost unlimited – I have had tanks where turf made up most of the aquarium’s growth. A certain Takashi Amano had a phase when he liked to arrange aquariums exclusively with this plant – without the use of any fertilizers.
In my opinion, whoever is thinking about a suitable plant, where the result should be a dense compact lawn without excessive care and maintenance requirements, will do best to reach for E. tenellus and omit e.g. the species Sagittaria subulata (because of its “aggressiveness” and large stature), as well as e.g. the various representatives of the genus Lilaeopsis (because of their demanding nature). It is suitable for smaller tanks as well as for larger aquariums – however, care must be taken to ensure sufficient and direct lighting.