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Crytocoryne lucens

Alternate Names:

Green Crypt, Water Trumpet, Lucens Crypt

Cryptocoryne lucens is a classic, beautiful, easy, and highly adaptable aquarium plant well-suited to setups with or without CO2.

Care At-A-Glance

Difficulty: Easy

Type: Rosette with rhizomes. Root Feeder

Size: Leaves 10-20cm

Position and Usage: Can be used across various zones in the aquarium, from foreground to background, depending on the aquascape design, size of the aquarium, and how plants are maintained.

  • CO2: While all will eventually get quite tall, CO2 can make this plant grow very fast and dense!

Growth Rate:

  • With CO2: Medium to very fast depending on the lighting. Can quickly grow in densely and recommended for background use

  • Without CO2: Very slow to slow - makes for a nice foreground plant requiring little maintenance

Lighting: Thrives under a broad range of lighting conditions, from low (1/5) to high (5/5).

  • CO2 will increase the growth speed and robustness under the same lighting conditions resulting in very dense stands with large individual plants and countless plantlets. It will have a darker coloration as well.

CO2: Not required, which suits hobbyists looking for low-maintenance plant options for the foreground and midground. Crypt lucens will grow much faster, denser, and taller with CO2 making it an excellent background plant for CO2 injected tanks.

Water Conditions: Tolerates a wide temperature range, from 65 to 88°C - some claim it can even tolerate a wider range.

pH: Prefers neutral water at 6.5 to 7.5 with some evidence that it can tolerate pH from 5.0 to 8

  • Without CO2: Keep at neutral or slightly alkaline as this plant can use bicarbonate which becomes less available at more acidic pH

  • CO2: Can be kept as low as 5.5-6.5 with few problems - which is the standard range for most planted aquariums

Water Hardness: 3dGH - 10dGH (Very soft to "moderately hard"). Suitable for 99% of all US tap water.

Propagation: Reproduces primarily through runners which will result in plantlets growing out around the mother plants. It is particuarly prolific with CO2 and a rich substrate where it can quickly cover quite a large area.

  • Like all Crypts, C. lucens can also be manually divided to encourage propagation by cutting the rosette center in half radially with a sharp blade. We recommend dividing only larger, mature plants and avoid more than four divisions each time.

Special Requirements: Prefers a nutrient-rich substrate for optimal growth as it is an obligate root feeder. Most substrates in a planted aquarium are more than adequate and for low-tech aquarists growing this plant without CO2, avoid aqua soils - especially more acidic ones. Stick to flourite or other passive substrates. Root tabs will be appreciated especially if fertilizing with CO2.

  • Susceptible to "Crypt melt" (especially without CO2 fertilization) where the top of the plant appears to die but the rhizomous roots regenerate a new plant afterwards.

  • Other than that, this is one of the easiest aquarium plants.

Detailed Information


Cryptocoryne lucens is an extremely easy-to-grow and simultaneously fascinating aquarium plant found in most aquariums with live plants for decades. It is the quintessential “low-tech” plant that requires only modest lighting and no CO2 supplementation. In even the most basic planted aquarium setups, it will grow beautifully - even if it takes some time. 

The same is true for many (but not all) Cryptocoryne species. Because of the extremely variable conditions in their natural habitats many of these plants have had to be ready to survive and thrive in a huge range of environmental parameters. It is capable of using bicarbonate as an inorganic carbon source when CO2 is low.

References and Further Reading

Walstad, D. (2013). Ecology of the Planted Aquarium: A Practical Manual and Scientific Treatise for the Home Aquarist. Echinodorus Publishing.

Kasselmann, C. (2003). Aquarium Plants. Krieger Publishing Company.

Hiscock, P. (2003). Encyclopedia of Aquarium Plants. Barron's Educational Series.

Othman, A. S., & Mohd Shukri, M. A. (2010). Cryptocoryne of Peninsular Malaysia. Penerbit Universiti Sains Malaysia.

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