Rotala wallichii

Quick facts

Max height

30 cm

Growth rate

fast

Difficulty

advanced

Placement

midground, background

Propagation

stem cuttings

Water parameters

Temperature

22–28°C

pH

5.5 to 7.0

Hardness

0 to 8 dGH

Light and nutrients

Lighting

very high

CO2

required for healthy growth

Substrate

nutrient rich

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

will be eaten by mollies, silver dollars, large goldfish, and other plant-grazers

Diggers (corydoras, loaches)

may get uprooted by active diggers

Root-disturbing fish

sensitive to root disturbance, plant where roots stay undisturbed

Habitat

Native to Southeast Asia, found in marshes and shallow waterways. The species (Rotala wallichii) has extremely fine, needle-like leaves arranged in dense whorls along thin stems. Under high light with CO2, the whorls develop vivid pink to magenta-red coloring that makes it one of the most visually striking stem plants available. The fine-textured leaf whorls create a soft, feathery appearance similar to Myriophyllum but with the color potential of a premium red Rotala. Considered one of the more demanding Rotala species in the aquarium hobby, suited to experienced keepers with established high-tech setups. Named after Nathaniel Wallich, the Danish-born botanist who worked extensively in India and Southeast Asia in the early 19th century. The species is found in wetland habitats across its native range. In the aquarium trade, R. wallichii is positioned as a premium species for experienced keepers, and tissue culture availability has made it more accessible than it once was when only wild-collected specimens were available.

Care notes

Demanding. Requires high light (80+ PAR), pressurized CO2 (25-35 ppm), and meticulous nutrient management. Under suboptimal conditions, the lower portions of the stems shed their fine leaves and the plant deteriorates from the bottom up. Iron supplementation is critical for the pink-red coloration. The fine, needle-like leaves trap detritus and are vulnerable to algae in unbalanced tanks; stable, consistent dosing of macronutrients and micronutrients is essential. Plant stems in dense groups (10+) for the best visual effect. Growth under optimal conditions is moderate. Trim tops and replant; the cut stems may or may not produce side shoots reliably (less dependable than R. rotundifolia in this regard). Temperature: 22–28°C. pH 6.0-7.0 (prefers slightly acidic water). Soft water (GH 2-8). Very hard or alkaline water causes deterioration. Not a beginner plant. For keepers with dialed-in high-tech setups, the vivid magenta whorls of healthy R. wallichii are among the most beautiful sights in aquascaping. Available from specialty retailers as tissue culture.

Further reading

• CO2 injection for planted tanks: what it costs, what it does, and when to skip it