Helanthium quadricostatus (Helanthium bolivianum 'Quadricostatus', Echinodorus bolivianus 'Magdalenensis', Echinodorus quadricostatus, Chain Sword, Amazon Chain Sword Plant, Dwarf Amazon Sword Plant)
A beautiful light green rosette plant from Central and South America that is extremely undemanding and easy to grow and well suited to beautiful foregrounds in low-tech tanks. H. quadricostatus resembles a slightly larger, more robust Helanthium tennelum, Helanthium quadricostatus has very reasonable lighting requirements and thrives without CO2. This fairly small, fast growing plant is suitable for any tank and will quickly spread as a lawn. It's crisp, green leaves are serene to look at and contrast nicely with darker green plants. It grows well in patches where adults will send runners to produce new plants nearby. It is one of the easiest plants, most rewarding plants in our catalogue.
Difficulty: Very Easy
Type: Rosette plant with stolons (runners)
Size: 7-10 cm in height
Position and Usage: Extremely versatile: Lawn, Foreground, Midground and Background (in very small tanks)
Growth rate: Fast
Lighting: 1/5 - 3/5
Temperature: 18-30°C (20-26°C optimum)
Water Conditions: pH between 5 to 7.5, water hardness unimportant
CO2: Not required
Propagation: Runners (Stolons) - baby plants may be cut off stolons (runners) and planted independently.
Special Requirements: Very few special requirements. As a root feeder H. quadricostatus does appreciate a nutrient rich substrate and a neutral to acidic pH that is common in planted aquariums. Does quite well in even inert aquarium gravel in an existing tank that has been enriched with fish poop and food.
Emersed: Grows well in terrariums, Wabi Kusa and Paludariums. When fully emersed, rosettes are ~10cm tall and 20cm across. Will produce flowers, fruits and seeds.
Helanthium 'Quadricostatus' (Dwarf Sword Plant)
Discovered in 1955 and known to most older aquarists as the Dwarf Sword Plant (Echinodorus bolivianum, Echinodorus quadricostatus or Echinodorus magdalenensis), Helanthium 'Quadricostatus' is a classic aquarium beauty that has been grown for generations as a smaller alternative to the popular (though poorly defined) Amazon Sword Plant. It is a one of the rare foreground plants that does well without CO2 in even moderate lighting.
H. 'Quadricostatus' is not only beautiful and well suited to aquariums but is also extremely undemanding and can be used in the simplest low-tech setups. Not only does it not require CO2, it does not require much lighting and will grow satisfactorily with only a modern "kit light". H. Quadricostatus has been kept in aquaria before the Moon Landing (albeit under many different names) so it's requirements are fairly basic.
Today, higher lighting and CO2 do make a difference in the growth speed, form, coloration and density so if you have a high tech tank, this plant will take full adavantage of the ameneties on offer.
The Dwarf Sword Plant is a classic "rosette plant" where the leaves grow out of a "crown" where the main shoot meets the roots. Like any rosette plants, H. 'Quadricostatus' is a heavy root feeder which means it appreciates either a nutritious (ie. established) substrate or benefits enormously from substrate fertilization with root caps. The plant should rather quickly develop a vast root network and after that, is virtually impossible to kill.
Like all Sword Plants, healthy specimens send "runners" (stolons) under the substrate from which nodes turn into new plants. These baby plants can be left to their own devices or be separated from the mother plant and planted elsewhere. Given good lighting and even without CO2, you will soon have plenty of little baby plants for your aquascaping needs.
H. 'Quadricostatus' is a characteristic light green color and looks best when planted in groups where it takes on dense hedge-like appearance in the midground or foreground. It's leaves will take on a shorter and wider appearance once planted in the aquarium.
Unlike the closely related Echinodorus genera of Sword Plants, Helanthium 'Quadricostatus' stays quite small and is suitable for even nano-aquariums. It is larger than the Pygmy Chain Swords (Helanthium tenellum) and thus makes a much more dramatic "specimen" plant in either the foreground or midground. It can even be grown as a beautiful lawn or carpet-type plant in larger, taller tanks.
Hailing from the tropical and subtropical environments of equatorial Central and South America, this plant prefer slightly acidic to neutral water which is normally par for the course in planted aquariums so it should thrive in the most common water conditions found in the hobby. Water hardness does not seem to matter except that plants grown in softer water may be more easily prone to iron deficiency which is easy to resolve.
The jury is still out on whether this is the same plant as Echinodorus bolivianus - they are visually indistinguishable when grown submerged and have very similar requirements. However, emersed-grown H. quadricostatus has been observed to be shorter than it's doppleganger and some scientific papers suggest that a H. quadricostatus is a "triploid" plant. It produces "four ribbed" fruits which lend the plant it's scientific name. Though hypothesized to be a mutation of another Helanthium plant (such as Bolivianus), the evidence is too thin to affect its official classification.