Hygrophila angustifolia - Immersed Potted Plant

Hygrophila angustifolia (often sold as "Hygro Blue" or "Narrow-leaf Hygrophila") is a graceful, fast-growing stem plant with long, ribbon-like leaves that sway in the current. Easy and forgiving, it’s excellent for adding height and movement to the background while soaking up excess nutrients in new or heavily stocked aquaria.

Origin

• Region: Southeast Asia

• Habitat: Slow to moderate rivers and floodplains; often emergent in the dry season

Physical characteristics

• Form: Upright stems with opposite nodes; readily branches after trimming

• Leaves: Narrow, strap-like, typically 1–2 cm wide and 10–25+ cm long submerged

• Colour: Fresh mid-green; tips may bronze slightly in strong light

• Height in aquaria: Commonly 30–60+ cm; easily reaches the surface in tall tanks

Aquarium requirements

Difficulty

• Level: Easy

Lighting

• Requirement: Medium light is sufficient; medium–high yields denser, broader leaf rosettes and shorter internodes

• Too little light → lanky stems and sparse bases

CO₂

• Demand: Low–medium

• Thrives without injection; CO₂ ~10–20 mg/L increases speed, leaf size and bushiness

Nutrients & substrate

• Feeding: Good water-column uptake and strong root feeding

• Substrate: Inert or active; grows best with nutrient-rich substrate or root tabs

• Fertilisation: Use a complete NPK + trace regimen

  • Pale new leaves → often iron/micros

  • Pinholes/edge necrosis → often potassium

  • General yellowing/slow growth → nitrogen

Water parameters (guideline)

• Temperature: 20–28 °C (tolerates 18–30 °C)

• pH: 6.0–7.5

• GH: 3–12 °dGH

• KH: 1–8 °dKH

• Flow: Gentle to moderate; leaves look best with some current

Planting & spacing

• Plant stems 3–5 cm apart so light reaches the lower nodes

• Use as a background mass or along the back corners to frame the scape

• Leave clearance from filters/intakes to prevent leaves being drawn in

Propagation

• Cuttings: Trim 10–15 cm apical tops and replant the tops; they root quickly

• Side shoots: Pinch and plant as new stems

• Periodically remove woody, leafless lower sections and refresh with vigorous tops

Maintenance

• Hedge trim: Cut the group to height, leaving 5–10 cm stumps; multiple new shoots emerge

• Top-replant reset: Uproot, keep the best tops, replant; discard old bases

• Keep leaves clean with steady nutrients/CO₂ (if used) and regular water changes

Aquascaping use

• Tall, flowing background that adds movement and a calm, riverine feel

• Softens hardscape lines and contrasts well with carpets and fine-textured stems

• Great “nutrient sponge” during the first months of a planted tank

Companion compatibility

• Community-safe; provides shelter for small fish and shrimp

• May be nibbled by herbivores (goldfish, silver dollars) or uprooted by large diggers—avoid such tank mates

Lifecycle & emersed form

• Perennial; easily grown emersed in humid conditions with thicker leaves

• Transitions back to submerged growth after a short adaptation period

Common issues & diagnostics

• Bare lower stems: Not enough light at the base → thin/space the group, increase light, or reset by top-replanting

• Pale/stunted new growth: Micronutrient or CO₂ limitation under stronger light → improve dosing and CO₂ stability

• Algae on leaves: Light–nutrient imbalance or inconsistent CO₂ → shorten photoperiod, maintain nutrients, improve flow

Special features / benefits

• Rapid growth outcompetes algae and buffers nutrient swings

• Ideal beginner background stem that still looks elegant in advanced layouts

Origin
Country or continent where a plant is the most common. Cultivars arise or are bred in cultivation.

Growth Rate
Growth rate of the plant compared to other aquatic plants.

Height
Average height (cm) of the plant after two months in the tank.

Light Demand
The average or medium light demand of an aquarium plant is 0.5 W/L.

CO2 Demand
A medium need in CO2 is 6-14 mg/L. A high demand in CO2 is approx. 15-25 mg/L.