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Form of Cryptocoryne crispatula

Cryptocoryne tonkinensis

Cryptocoryne crispatula var. tonkinensis

One of 3 forms of Cryptocoryne crispatula · See all forms →

Also known as Cryptocoryne crispatula 'Tonkinensis', Crypt tonkinensis

FreshwaterRosetteRunnersRhizome division

Cryptocoryne tonkinensis (Cryptocoryne crispatula var. tonkinensis)
Vitro Culture · Used with permission

Forms · Cryptocoryne crispatula

See all 3 →

Care at a glance

Light
Medium light
CO2
CO₂ beneficial
Temperature
68–82°F
20–28°C
Max height
19.7 in
50 cm
Growth rate
Medium
Placement
Background
Type
Rosette
pH
6.0–8.0
Hardness
5–18 dGH
Spread
5.9 in (15 cm)
Nutrient uptake
Root + water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Araceae
Origin
Northern Vietnam and southern China (Guangxi)

Overview

Cryptocoryne tonkinensis is a finer-boned relative of balansae, used as a background or tall midground grass. It is an easy crypt with narrow ribbon leaves.

Did you know

In a tank, the millimeters-wide ribbon leaves of Cryptocoryne tonkinensis are regularly mistaken for Vallisneria or a grass. The giveaway is the crypt habit of advancing in slow steps from runners instead of racing across the tank.

Caring for Cryptocoryne tonkinensis

Plant Cryptocoryne tonkinensis in a nutrient-rich substrate with root tabs. Its ribbon leaves reach for the surface and sway in the flow. Let it establish, and do not move it once it has settled.

Give it medium light. CO2 is optional, but it noticeably improves density. It feeds through both its roots and its leaves, so a liquid fertilizer helps alongside the root tabs. It handles hard, alkaline water well and suits 68 to 82°F (20 to 28°C).

It grows at a moderate pace and spreads by runners into loose stands. You can also divide the rhizome into pieces with several leaves each. Keep parameters steady, and expect melt after planting or big water changes.

Good to know

Cryptocoryne tonkinensis is a botanical variety of Cryptocoryne crispatula in the family Araceae, not a cultivar. Its full name is var. tonkinensis (Gagnep.) N. Jacobsen, after Tonkin, the old European name for northern Vietnam. It is one of the narrowest-leaved forms of the crispatula complex, with grass-like blades a few millimeters wide where var. balansae is broader and puckered. Flowgrow notes that an even narrower plant from eastern Thailand was long traded under this name and is now described as var. kubotae. Shop plants deserve a second look.

In the wild

Cryptocoryne tonkinensis grows in northern Vietnam and southern China (Guangxi), rooted in sand and gravel in streams and rivers with strongly seasonal flow. Like the rest of the crispatula group, it is a rheophyte. It spends high water fully submersed with its leaves streaming in the current, and it flowers emersed as levels drop.

Common questions

Is Cryptocoryne tonkinensis a different species from Cryptocoryne crispatula?

No. Cryptocoryne tonkinensis is a form of Cryptocoryne crispatula. It reaches about 19.7 in (50 cm), against 23.6 in (60 cm) for the species. It also differs in growth rate, pH, spread and temperature.

Does Cryptocoryne tonkinensis 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 tonkinensis need CO2?

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

How much light does Cryptocoryne tonkinensis need?

Cryptocoryne tonkinensis wants medium light. A light sold for planted tanks covers it.

Does Cryptocoryne tonkinensis need root tabs?

They help. Cryptocoryne tonkinensis 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 tonkinensis?

Cryptocoryne tonkinensis 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 tonkinensis grow?

Cryptocoryne tonkinensis grows to about 19.7 in (50 cm) tall. It grows at a moderate pace.

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