Dennerle Heteranthera Zosterifolia

Heteranthera zosterifolia, commonly known as Stargrass or Water Stargrass, is an aquatic plant from Brazil and surrounding South American countries, where it grows in slow-moving rivers and flooded plains. In the aquarium, it is characterized by narrow, grass-like leaves arranged in star-like whorls at each stem node — a distinctive arrangement that creates a fine, airy, natural-looking texture as the stems grow upward.

Stargrass is a fast-growing species under good light and CO2, making it one of the most effective aquatic plants for quickly establishing background coverage in new aquascapes. Its fine leaf texture provides a soft, natural background that contrasts well with broader-leaved midground and foreground plants.

The plant can be grown without CO2 in lower-light conditions, though growth is much slower. Under strong light and CO2, it grows vigorously and requires frequent trimming to prevent reaching the surface. Trimmed tops can be replanted to create denser groupings.

Star Grass is also useful in biologically establishing new aquariums due to its rapid nutrient uptake capacity — it outcompetes algae for ammonia and nitrate during the cycling period of a new planted tank.

Light: Medium to high light (20–60+ PAR). Grows in lower light without CO2 but more slowly and less densely.

CO2: Optional but strongly beneficial. CO2 injection (15–25 mg/L) produces rapid, lush growth.

Placement: Background plant. Grows quickly upward — plant in the back of the aquascape in groups of 5–10 stems. Trim frequently when vigorous.

Propagation: Fast. Cut tops and replant stems to create bushier groupings. Remove and replant lower stems that become bare.

Maintenance: Regular trimming required in good conditions. Trim tops and replant. Remove any stems with bare lower sections.

Water Parameters: pH 6.0–8.0, temperature 22–28°C, adaptable to a range of water chemistry.