Cryptocoryne thwaitesii

Care at a glance

Overview

A crypt for experienced growers, not for the community tank. It demands soft, acidic water and an acidic substrate, and the specialist literature calls it flatly unsuitable for a hard-water aquarium. Most people who succeed grow it emersed or half emersed in a pot with decomposing leaf litter, and only move well-established divisions underwater, in dim light and soft water. Buy propagated material only; wild collection is one of the pressures on its shrinking Sri Lankan habitat.

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 plants sit half emersed on the banks with their rhizomes in decomposing leaf litter. It shares this shrinking wet-zone habitat with C. alba and C. bogneri, and the crypts of the region are all considered severely threatened.

Good to know

One of the earliest described water trumpets, named by Schott in the 19th century for George H. K. Thwaites, the British botanist who ran the Peradeniya botanic gardens in Ceylon. It belongs to the family Araceae. The broad, ovate leaves have finely waved margins and a rough surface, and the spathe limb varies remarkably between populations, from pure white to deep red with variable spotting.

Did you know

The spathe of C. thwaitesii is so variable that flowers from different streams can look like different species, ranging from pure white to deep red.

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