TankBud

Cryptocoryne thwaitesii

Also known as Crypt thwaitesii

FreshwaterRosetteRunnersRhizome division

Cryptocoryne thwaitesii (Cryptocoryne thwaitesii)
Buce Plant · Used with permission

Care at a glance

Light
Low light
CO2
CO₂ beneficial
Temperature
72–82°F
22–28°C
Max height
5.9 in
15 cm
Growth rate
Slow
Placement
Midground
Type
Rosette
pH
5.0–6.5
Hardness
0–6 dGH
Spread
5.9 in (15 cm)
Nutrient uptake
Root + water column
Growth region
Submersed or emersed
Difficulty
Difficult
Family
Araceae
Origin
Southwestern Sri Lanka

Overview

Cryptocoryne thwaitesii is a slow-growing Sri Lankan crypt for the midground. It is rated difficult and suits experienced growers rather than the community tank.

Did you know

The spathe of Cryptocoryne thwaitesii varies so much that flowers from different streams can look like different species. Its color runs from pure white to deep red, with variable spotting.

Caring for Cryptocoryne thwaitesii

Grow Cryptocoryne thwaitesii in soft, acidic water over an acidic substrate, around pH 5 to 6.5 and 0 to 6 dGH. The specialist literature calls it unsuitable for a hard-water aquarium. Most growers who succeed start it emersed or half emersed in a pot with decomposing leaf litter, and move only well-established divisions underwater.

Keep it in dim light once it goes under, since it is a low-light plant. CO2 is optional, though it speeds up the slow growth. It feeds through both its roots and its leaves, so pair root tabs near the roots with a liquid fertilizer. Keep the water at 72 to 82°F (22 to 28°C).

New plants appear along its runners, and you can cut one free once it has roots. An established clump can also be divided at the rhizome. Buy propagated plants only, because wild collection is one of the pressures on its shrinking Sri Lankan habitat.

Good to know

Cryptocoryne thwaitesii is one of the earliest described water trumpets, in the family Araceae. Schott named it in the 19th century for George H. K. Thwaites, the British botanist who ran the Peradeniya botanic gardens in Ceylon. Its broad, ovate leaves have finely waved margins and a rough surface.

In the wild

Cryptocoryne thwaitesii grows in the rainforest of southwestern Sri Lanka, on shaded stream banks in soft, acidic water. In the dry season the plants stand half out of the water, rooted in the leaf litter of the banks. It shares this shrinking wet-zone habitat with C. alba and C. bogneri, and the crypts of the region are all considered severely threatened.

Common questions

Does Cryptocoryne thwaitesii need to be planted in the substrate?

Yes. Bury the roots and leave the crown, where the leaves join, just above the substrate.

Does Cryptocoryne thwaitesii need CO2?

No, but it helps. Cryptocoryne thwaitesii can grow without injected CO2, and added CO2 makes it grow faster.

How much light does Cryptocoryne thwaitesii need?

Cryptocoryne thwaitesii is a low-light plant, and the light that comes with a standard tank kit is enough for it.

Does Cryptocoryne thwaitesii need root tabs?

They help. Cryptocoryne thwaitesii takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate Cryptocoryne thwaitesii?

Cryptocoryne thwaitesii propagates by runners and rhizome division. New plants grow along its runners. Cut one free once it has roots and plant it. Cut the rhizome into pieces with several leaves each, then tie or plant each piece.

How tall does Cryptocoryne thwaitesii grow?

Cryptocoryne thwaitesii grows to about 5.9 in (15 cm) tall. It grows slowly and rarely needs trimming.

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