Hygrophila polysperma sp Rosanervig

Common Names & Taxonomy

• Scientific Name: Hygrophila rosanervis

• Common Names: Often sold as "Rosanervis," "Rosae Nervis," or "White-Veined Hygrophila."

• Important Note: There is significant confusion about its true identity. It is not a naturally occurring species but is widely believed to be a cultivated variant or hybrid, possibly of Hygrophila polysperma or related species. The "rosanervis" name is a horticultural trade name, not a valid botanical one.

Key Identifying Features & Appearance

This plant is prized almost entirely for its remarkable leaves:

• Leaf Color & Pattern: The most striking feature is the bright white or creamy-white veins that contrast dramatically against a background color that can range from deep green to pink, red, or even purple. The intensity of the pink/red color depends heavily on lighting and nutrient conditions.

• Leaf Shape: Leaves are lanceolate (spear-shaped) to elliptical, with a smooth margin.

• Growth Form: It is a stem plant that grows upright and can be bushy when regularly trimmed. It can grow both submerged (fully underwater) and emersed (partly above water).

• Size: Individual leaves can be 3-7 cm long. The stem can reach 20-40 cm (8-16 inches) or more in height.

Origin & Habitat

As a cultivated variant, it doesn't have a natural wild habitat. Its presumed parent species (like H. polysperma) originate from South and Southeast Asia.

Care Requirements in the Aquarium

It is considered a moderately demanding plant, requiring stable conditions to thrive and show its best colors.

1. Lighting: High lighting is crucial. Intense light is needed to bring out the vibrant pink/red colors and maintain the strong contrast of the white veins. Under low light, it tends to stay green and may become leggy.

2. Nutrients: Requires a nutrient-rich substrate and regular fertilization in the water column. Deficiencies in macronutrients (Nitrogen, Potassium, Phosphate) or micronutrients (Iron, Manganese) will result in poor growth, loss of color, or melting.

3. CO2: Supplemental CO2 injection is highly recommended. While it may survive without it, growth will be slower, less compact, and colors will be less vivid.

4. Water Parameters:

   • Temperature: 20-28°C (68-82°F)

   • pH: 6.0 - 7.5

   • Hardness: Prefers soft to moderately hard water.

5. Maintenance: Regular trimming encourages bushy, lateral growth. The top cuttings can be replanted to propagate the plant easily.

Special Considerations

• "Fragile" Reputation: It sometimes gets a reputation for being delicate or "melting" suddenly. This is usually due to unstable conditions, changes in water parameters, or nutrient deficiencies.

• Algae: Because it requires high light and nutrients, it can be susceptible to algae growth on its leaves, especially if there is an imbalance (e.g., too much light without adequate CO2 or nutrients).

Uses in Aquascaping

• Midground to Background: Due to its height, it's best placed in the midground or background of an aquarium.

• Color Contrast Focal Point: Its unique white-veined, pink leaves make it an excellent centerpiece or focal point to draw the eye.

• Bushy Grouping: When planted in groups and trimmed well, it forms a dense, colorful bush that adds great texture and depth to the aquascape.

Summary

Hygrophila rosanervis is a beautiful, color-contrast stem plant that acts as a living indicator of good aquarium plant health. It rewards high light, CO2 injection, and consistent fertilization with spectacular foliage, making it a favorite among intermediate to advanced aquascapers. Its main appeal is the stunning visual pop it adds to a planted tank.