Echinodorus osiris

Scientific name: Echinodorus osiris

Family: Alismataceae

Usual maximum size in aquariums: 20 - 50 cm (7.87 - 19.69 inch)

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Recommended pH range for the species: 6.5 - 7.5

Recommended water hardness (dGH): 4 - 18°N (71.43 - 321.43ppm)

0°C 32°F30°C 86°F

Recommended temperature: 21 - 27 °C (69.8 - 80.6°F)

Reproduction of the plant: Runners

Origin (in the wild): South America

How fast these plants grow: Fast

Recommended substrate: Fine gravel

Demands on lighting: Medium

Ideal placement in a fish tank: Middle

Common Name

Melon Sword

Origin

Echinodorus osiris is native to South America, specifically found in regions of Brazil. It typically grows along riverbanks, wetlands, and floodplains, where it thrives in both submerged and emersed conditions.

Growing Conditions

This plant adapts well to both submerged and emersed environments. When grown submerged in aquariums, it develops large, elongated leaves that may show a reddish hue, especially in cooler temperatures. In emersed setups, such as paludariums or shallow ponds, it may produce flower stalks and propagate via adventitious plantlets.

Echinodorus osiris prefers moderate lighting, though it tolerates slightly lower levels. Brighter lighting encourages reddish coloration in younger leaves, which later mature into deep green tones. Ideal water parameters include a pH between 6.5 and 7.5 and water hardness of 4 – 18 dGH. It thrives in temperatures ranging from 21 – 27°C (69.8 – 80.6°F). A nutrient-rich substrate is essential for optimal growth.

Planting Area

Due to its impressive size and spread, Echinodorus osiris is best placed in the middle to background of the aquarium. It serves as a striking centerpiece in medium to large tanks. In smaller aquariums, be cautious, as it can outgrow the available space. Its broad rosette and upright growth habit provide natural shelter for fish.

Propagation

Echinodorus osiris reproduces through runners (stolons) that produce adventitious plantlets. These daughter plants form around the mother plant, especially in nutrient-rich conditions. Once the plantlets develop several roots and leaves, they can be carefully separated and replanted in the substrate. For successful establishment, ensure adequate fertilization—using root tabs is highly recommended.

Difficulty

Echinodorus osiris is considered an easy-to-care-for plant, suitable even for beginners. However, its fast growth and nutrient demand mean that consistent care is important. It may require regular trimming and fertilization to maintain optimal health and visual appeal.

Short Description

Echinodorus osiris, known as Melon Sword, is a robust and decorative sword plant popular in freshwater aquariums. Its ability to produce reddish new leaves that mature into broad green foliage adds vibrant color and texture to the aquascape. This species is ideal as a focal point and offers excellent cover for fish due to its spreading rosette shape.

The plant benefits from root tab fertilization, especially during the early stages after planting. It is relatively undisturbed by herbivorous fish due to its taste-repellent foliage, making it suitable even for tanks with plant-nibbling species.

Although tolerant of lower lighting, stronger illumination enhances its red coloration. Yellowing or fading leaves may indicate iron deficiency, which can be corrected by adding iron-based plant supplements.

Echinodorus osiris is suitable for both submerged and emersed growth and may produce flowers when grown above water. In all, it is a hardy, fast-growing plant that thrives in well-maintained aquariums and brings visual impact and biological balance to any setup.

Frequently Asked Questions

• Can Echinodorus osiris be grown in low light conditions?

  Yes, it can survive in low to medium light, but its growth will be slower and less colorful. For vibrant reddish leaves and robust growth, moderate to bright lighting is recommended.

• Does Melon Sword need CO₂ injection?

  CO₂ supplementation is not required but can enhance growth. The plant performs well in non-CO₂ tanks if provided with sufficient nutrients and lighting.

• Why are the leaves of my Echinodorus osiris turning yellow?

  Yellowing leaves are often a sign of iron deficiency or lack of nutrients in the substrate. Try using iron-rich root tabs or liquid fertilizers to correct the issue.

• Can this plant be grown emersed?

  Yes, Echinodorus osiris can grow emersed in paludariums or shallow water setups. When grown above water, it may even produce small white or pinkish flowers.

• How often should I prune Melon Sword?

  Prune older or damaged leaves as needed to maintain its shape and prevent overcrowding. Occasional trimming also encourages healthier new growth.

• Is it safe to grow Echinodorus osiris with herbivorous fish?

  Yes. This plant is generally avoided by herbivorous species because its leaves are less palatable. It's a great option for tanks with plant-nibbling fish.