Aquarium Cryptocoryne Plants
Although the proper scientific name of this aquarium plant genus is Cryptocoryne, they are commonly referred to as “crypts.”
Text and photos Robert Paul Hudson
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The name Cryptocoryne is a funny-sounding name for a group of plants that have been popular in the aquarium hobby for decades. The word comes from the Greek word krypto, meaning hidden, and koryne, meaning stick, referring to the hidden (by the basal wall) spadix (an inflorescence, or a cluster of flowers on a stem, where the small flowers are crowded on a thickened, fleshy axis) in the flower structure. There are 58 recognized species and of these less than a dozen are suitable for the aquarium. Of those suitable species, there are several cultivated variations (known as cultivars) that produce different leaf colors and shapes, and there are regional habitat variations of species as well.
|Five Keys to Cryptocoryne Success|
• Nutrient-rich substrate
• System stability
• Appropriate water conditions for the species being kept
• Plenty of patience
• Limited transplants or
preferably no transplants
|Click image to enlarge|
After Cryptocoryne wendtii, C. undulata (pictured) is probably the second easiest crypt to grow and maintain in aquaria.
The spadix, a flowery structure typical of the family, is the “stick” that contains the male and female reproductive organs. The stamens (a pollen-bearing organ in a flower) are located in the top of the spadix, while the stigmas (the free upper part of the style — the slender part between the stigma and the ovary — of a flower where pollen falls and develops) are at the bottom close to the chamber cavity called the kettle. Pollen and eggs also reside in the kettle, which has bright colors that attract insects for pollination. Many of the Cryptocoryne species would be impossible to distinguish if not for the flower structure, which does not bloom underwater.
These leaf shapes range from long and straplike to ovate (round or oval), and even grasslike, to very small and spoon shaped. Typically, the colors are dark earthy tones of green, red and bronze and are prized in the aquarium for distinctive groupings or rows.
Typical habitats of Cryptocoryne are meandering rivers in lowland forests. They also live in seasonal flood pools or flooded river banks. Although the proper scientific name of the genus is Cryptocoryne, they are commonly referred to as “crypts.”
Most of the more common aquarium species come from Sri Lanka, including Cryptocoryne wendtii (including several varieties and hybrids), C. walkerii (otherwise known as C. lutea), C. undulate and C. becketii (including the variety known as “petchii”). These grow in small streams in soils of various types (sandy loam, clay, leaf litter) and mostly in soft acidic waters.
These species adapt readily to the aquarium and tolerate a wider variety of water conditions than other Cryptocoryne species and have been mass-produced in plant farms worldwide. In recent years, additional species found in Malaysia, Indonesia, Sumatra and Borneo have been introduced to the hobby and while some are more challenging than others, all have proven to be suited to aquaria.
|Click image to enlarge|
Cryptocoryne parva is the world’s smallest crypt, growing only from 2 to 3 inches in height.
Cryptocoryne crispatula var. balansae can take a long time to become established in an aquarium, but the plant is well worth the wait.
Specific care requirements vary from one species to another. In general, most aquarium crypts are adaptable to moderately acidic to moderately hard water with three basic requirements: fertile substrate, system stability and clean water. These three requirements must be met in order to avoid “crypt-melt” syndrome. While these plants are often thought of as low-light plants, only a few species tolerate low-light levels. All crypts will flourish under more intense light.
Like other plants, crypts need light and nutrients in order to grow and develop to their full potential. Two or three watts of fluorescent light per gallon of water should be enough light for most species. The color of the light is determined by the Kelvin rating and is more for aesthetic benefit than plant growth. A good daylight bulb around 6500 K is my preference.
Another factor to be considered is the substrate. Like most rosette plants, crypts grow more vigorously in nutrient-rich soils. Typical neutral sandy soils or gravel will prove to be of no nutritional value for these plants. While most commercial aquarium substrates are clay gravel, which provides iron and other minerals but are free of organic material that will break down. Although these substrates provide no nitrogen or other macronutrients, they are considered safe because they are inert. Over time as an aquarium matures, organic material settles to the bottom of the substrate and provides a good source of nitrogen and some other macronutrients for the plants. This is the reason you often see Cryptocoryne species thriving in old aquariums that have subdued light and receive no supplemental fertilization.
Cryptocoryne species may suddenly have a complete meltdown, where all or most of their leaves simply disintegrate. The exact causes and circumstances of this has never been fully established. It has even been referred to as a disease.
It is known that various environmental conditions can trigger it. Sudden changes in temperature, water quality, nitrate or ammonia levels and transplant shock all may set off this condition. It has been observed happening in natural habitats during seasonal changes and periods of reduced rainfall. It could very well be a defense mechanism. If left undisturbed in stable conditions, the rootstock, or rhizome, will usually totally regrow new leaves within a few weeks to a few months.
The biggest mistake hobbyists make when this malaise strikes is thinking their crypts are dead and then preceding to throw out what’s left of the plants. Page 2>>
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