Species guide
Rotala rotundifolia Care Guide (Color Stem)
Aquatic plant
Rotala rotundifolia is the gateway color stem: it survives low-tech green, but pink/orange tops need medium–high light, CO₂, and regular pinching. If you want “red” with a desk lamp, pick a different plant.
- Stem
- Color with light+CO₂
- Pinch weekly
- Medium–high light
Quick facts
| Light | Medium–high for color; low = green + long internodes |
|---|---|
| CO₂ | Strongly recommended for tight pink tops |
| Temp | 20–28 °C |
| NO₃ / PO₄ | Lean–moderate; very high N can keep it greener |
| Trim | Pinch 1–2×/week; replant tops |
| Planting | Dense group, 1–2 cm between stems |
| Low-tech verdict | Lives, rarely colors |
| Height | 20–40 cm midground |
Overview
Rotundifolia is honest: alive ≠ photogenic. Low-tech it is a green filler. High-tech with CO₂ and a real PAR it can blush orange-pink. Do not buy it as a “red plant” for a 6 W clip light.
Easier stems: H. polysperma · wisteria. High-tech path: low vs high-tech · triangle. Background contrast: Vallisneria.
How to get color (or stay green on purpose)
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Step 1
Decide low-tech green vs high-tech color
Green: medium light, no CO₂, pinch anyway. Color: 30+ PAR at tops, injected CO₂, stable.
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Step 2
Plant a tight bunch midground
Sparse stems look weedy. 9–20 stems look like a bush after two pinches.
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Step 3
Pinch before internodes stretch
Weekly. Replant tops in front of old bottoms or restart the bunch.
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Step 4
Keep N moderate if you want pink
Excess nitrate + weak light = lime green. Iron helps, but light/CO₂ first.
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Step 5
Do not chase red with 14-hour lights
That grows BBA. Photoperiod 6–8 h with enough intensity beats long dim days.
Common problems
Always green, never pink
Why: Light/CO₂ too low.
Fix: Accept green or upgrade. See low vs high-tech.
Leggy with tiny tops
Why: Not pinching + low PAR.
Fix: Hard prune; replant tops closer to the lamp.
Melts after a big water change
Why: pH/KH swing with CO₂ off.
Fix: Match CO₂ on/off to lights. Slow KH changes.
GSA on older leaves
Why: Too much light / imbalance.
Fix: Trim old; check PO₄. Not a reason to quit the plant.
Tank mates
Gear for this species
Landen Aqua Soil Substrate for Natural Planted Aquarium, Plant or Shrimp Stratum, Clay Gravel and Stable Porous Substrate for Freshwater Aquarium, Black Color 40lbs
Substrate vàng chuẩn Iwagumi / Nature Aquarium.
Low-tech vs high-tech planted tank — Buy rotundifolia for a stem bush — not as a guaranteed red plant
FAQ
Will it turn red without CO₂?
Rarely more than a hint of pink at very high light. Plan on green low-tech.
Rotala H’ra vs rotundifolia?
H’ra is pickier and more orange. Master rotundifolia first. H’ra is a later Q1 article.
How often do I pinch?
Weekly in good light. Every 10–14 days low-tech.
Can it be a background?
It gets tall but floppy. Val or swords make a better back wall.
Does it need aquasoil?
Helps. Inert sand + liquid fert also works.
Good first color stem?
Yes if you already run CO₂. If not, grow hygro/wisteria first.
Aqua Plants Hub Editorial
