Cryptocoryne undulata

Quick facts

Max height

20 cm

Growth rate

slow

Difficulty

beginner

Placement

midground

Propagation

runners

Water parameters

Temperature

22–28°C

pH

6.0 to 7.5

Hardness

2 to 15 dGH

Light and nutrients

Lighting

low

CO2

not required, but boosts growth and color

Substrate

nutrient preferred

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

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

may get uprooted by active diggers

Root-disturbing fish

tolerates fish that disturb roots

Habitat

Native to Sri Lanka, growing in streams and river margins in the island's wet and intermediate climate zones. The species (Cryptocoryne undulata) has medium-length leaves (10–20 cm) with distinctly wavy (undulate) margins and a brownish-green to olive coloring that shifts toward reddish-brown under stronger light. The leaf surface often shows a hammered or slightly crinkled texture that adds visual depth. Sometimes confused with C. wendtii because of similar size, color, and overlapping trade names, but C. undulata has more pronounced leaf undulation and a slightly different leaf shape (more elongated). Taxonomic boundaries between C. undulata, C. wendtii, and C. beckettii have been debated for decades, and many plants sold under one name may actually belong to another. A medium-sized Cryptocoryne suitable for midground planting.

Care notes

Easy care, very similar to C. wendtii and C. beckettii in requirements and behavior. Low to moderate light, no CO2 injection needed, pH 6.0-8.0, soft to moderately hard water. Root tabs or nutrient-rich substrate for healthy growth. The wavy leaf margins add textural interest that smooth-leaved plants don't provide, and the undulation catches light at varying angles for subtle visual movement even in still water. Growth is moderate once established. Under higher light, the brownish-red tones intensify and the undulation becomes more pronounced. Susceptible to the standard Cryptocoryne melt during changes in water parameters or transplantation; leave roots in substrate and allow 2-4 weeks for regrowth. Propagation by runners; daughter plants appear 5–10 cm from the parent over several weeks. A group of 3-5 plants fills a midground section over a few months. Temperature: 22–28°C. Compatible with all community fish; the tough leaves resist nibbling from all but dedicated herbivores. Often sold alongside C. wendtii under generic labels in aquarium stores. For most practical purposes, C. undulata and C. wendtii are interchangeable in terms of care and aquascaping use.

Further reading

• How to cycle a fish tank
• Water chemistry for fishkeepers: pH, GH, KH, and what they mean