Hygrophila polysperma

Scientific name: Hygrophila polysperma

Family: Acanthaceae

Usual maximum size in aquariums: 25 - 45 cm (9.84 - 17.72 inch)

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Recommended pH range for the species: 5 - 8

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

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Recommended temperature: 21 - 26 °C (69.8 - 78.8°F)

Reproduction of the plant: Cuttings

Origin (in the wild): South Asia

How fast these plants grow: Fast

Recommended substrate: Gravel

Demands on lighting: Bright

Ideal placement in a fish tank: Background

Common Name

Indian Waterweed

Origin

Hygrophila polysperma originates from South and Southeast Asia, specifically found in regions such as India, Bangladesh, Bhutan, and Nepal. It thrives in slow-moving rivers, marshes, and flooded fields, adapting easily to different water conditions. Due to its rapid growth and resilience, it has spread beyond its native range and is now considered an invasive species in some parts of North America and Europe.

Growing Conditions

Hygrophila polysperma is a highly adaptable plant that can grow in both submerged and emersed conditions. In aquariums, it thrives when fully submerged, where it develops soft, vibrant green leaves. When grown emersed, the leaves become thicker and more rigid, and the plant may produce small blue flowers above the water surface.

This plant prefers bright lighting to encourage healthy, compact growth. Under lower light conditions, the stems may elongate, leading to sparse leaf development. A nutrient-rich environment with a pH range of 5 to 8 and water hardness between 4 - 18 dGH is ideal for optimal growth. It grows best in temperatures ranging from 21 - 26 °C (69.8 - 78.8°F). Using CO₂ supplementation can further enhance its growth rate.

Planting Area

Due to its fast growth and ability to reach 25 - 45 cm (9.84 - 17.72 inches), Hygrophila polysperma is best placed in the background of an aquarium. It creates a dense, lush appearance and provides excellent shelter for fish and fry. However, regular pruning is necessary to prevent it from overtaking the tank.

Propagation

Hygrophila polysperma propagates easily through cuttings. To propagate, take a cutting from the mother plant and remove the lower leaves. Carefully plant the cutting into the gravel substrate, ensuring that the stem is not crushed. Within a short period, the cutting will develop roots and establish itself as a new plant. Even detached leaves settling on the substrate may form new plants, making this species self-propagating under optimal conditions.

Difficulty

Hygrophila polysperma is considered one of the hardiest aquarium plants, making it an excellent choice for beginners. It is highly adaptable to a wide range of water conditions and does not require extensive care. However, due to its rapid growth, regular pruning is essential to prevent it from spreading uncontrollably and shading other plants.

Short Description

Hygrophila polysperma, commonly known as Indian Waterweed, is a fast-growing, low-maintenance plant that is perfect for planted aquariums. It provides a lush green backdrop, oxygenates the water, and serves as a natural hiding place for fish and fry. While it is easy to grow, its rapid spread requires regular trimming to prevent it from taking over the tank. This species can thrive in both submerged and emersed conditions, making it a versatile choice for aquariums, paludariums, and wetland setups.

Due to its aggressive growth rate, Hygrophila polysperma is considered invasive in some regions, so proper disposal of trimmings is recommended to prevent its spread in natural waterways.