Subclass Alismatidae
Order Alismatales
Family Araceae
Genus Cryptocoryne.
The native habitats of Cryptocoryne include the southern and southeastern regions of India, Bangladesh, Burma, Thailand, Vietnam, Southern China, the Malay Peninsula, the Indonesian islands, the Philippines, and Ceylon. Cryptocoryne remain consistently popular among ornamental aquarium enthusiasts. This is due to the great variety of their forms, coloration, sizes, and the absence of floating leaves. Most Cryptocoryne are quite large plants with a heavily shortened stem, leaves of various shapes and colors with thin, long petioles, and a fibrous root system. In Cryptocoryne, we find a full spectrum of colors, shades, and sizes. In their homeland, they grow in standing or slowly flowing shaded water bodies. These bodies of water are usually filled with water only during the rainy season. During droughts, the water level in them drops sharply, and Cryptocoryne begin to lead a semi-submerged or terrestrial lifestyle. At this time, flowering begins. Thus, keeping Cryptocoryne constantly underwater is not natural for them, but is the result of acclimatization.
Most Cryptocoryne can tolerate changes in lighting, as well as water hardness and acidity. Most importantly, they are adapted to coexistence in the same aquarium with plants from other families. Perhaps Cryptocoryne are most sensitive to temperature, since in their homeland it remains at the same level almost year-round — 25-27°C. In an aquarium at temperatures below 22°C, many Cryptocoryne grow poorly, and in colder water they may die. The optimal temperature for keeping Cryptocoryne is 22-26°C. Cryptocoryne are mostly bog plants. The main source of nutrition comes through the root system; thus, they can withstand fairly heavy silting of the substrate. Furthermore, Cryptocoryne possess symbiotic fungi whose mycelium is able to absorb nutrients from the soil solution under conditions extremely unfavorable for the roots due to the anaerobic process of organic decomposition (rotting). Of course, not all Cryptocoryne can be classified as shade-tolerant, let alone shade-loving plants. A lack of light usually manifests as an inelegant elongation of the petiole or a fading of coloration, but it rarely threatens the plant’s life.
One of the most important factors influencing the growth and reproduction of these plants is mineral nutrition. However, although nutrients reach Cryptocoryne regularly, they do so in minimal doses. Regular fertilizer dosing can easily ruin Cryptocoryne. Micro-dosing is carried out in only one way: stable water changes, effectively simulating water flow in the aquarium. Given that in natural water bodies this group of plants lives in a constant composition of flowing water, success can only be achieved by strictly adhering to the chosen regime in the aquarium. When considering a less frequent water change schedule, Cryptocoryne tolerate it more easily than almost any other plants. Cryptocoryne easily adapt to heavy, and most importantly, stable water changes. Cryptocoryne affinis can grow with almost no water changes. Substrate should be nutritious (5 cm), with added clay, peat, and charcoal. Planting should be done so that the root base remains above the substrate. Cryptocoryne dislike being transplanted (no more than once a year) and take a long time to adapt to the environment; some species take weeks to produce their first new leaf after transplantation. They should not be grown together with Vallisneria or Barclayia, as these inhibit them.
The placement of Cryptocoryne in a decorative aquarium depends on the aquarist’s taste, the size of the water body, the size of the plant, and the overall layout design. It is difficult to say in advance whether to place Cryptocoryne as single specimens or in groups. Everything depends on specific compositions and the aquarist’s capabilities. Cryptocoryne with bullate-leaved forms include: C. bullosa, C. coronata, C. hudoroi, C. keei, C. crispatula var. balansae, C. usteriana, and to some extent, certain forms of C. affinis. Usually, large species like C. usteriana and C. balansae are placed in the background; for the mid-ground, somewhat smaller Cryptocoryne are good — C. spiralis, C. bogneri, C. evae, C. siamensis, C. karthause, C. beckettii, etc. In the foreground, it is best to place Cryptocoryne such as C. lingua, C. nevillii, C. lucens, C. parva, C. minima, etc., or between the foreground and mid-ground to mask the petioles of large Anubias, Aponogeton, or Echinodorus. It is worth mentioning C. parva; it reproduces so slowly and is so small that it will decorate the foreground of even the smallest aquarium.
In the mid-ground, single specimens of C. retrospiralis look good, rising above other plants and spreading numerous leaves in different directions. The same can be said for C. balansae, which holds its corrugated brown-green leaves vertically. Cryptocoryne are also suitable for creating a “street” effect, depending on the size of the aquarium. In principle, bushes of Cryptocoryne wendtii and Cryptocoryne walkeri look magnificent for this purpose. Given how diverse both Cryptocoryne wendti and Cryptocoryne walkeri are, you can choose colors ranging from green to red and in various sizes. If the water column is low, Cryptocoryne x willisii look wonderful. Cryptocoryne planted in groups along the edges of the aquarium and occasionally in the foreground enhance the decorative effect. When planting young specimens and planning the composition, one should always remember the characteristic feature of Cryptocoryne: in the vast majority of cases, these are sparsely leaved plants that rarely form a dense crown and are best appreciated when viewed as single specimens.
Within individual species, there are variations in leaf shape and coloration, so reliable species identification is only possible based on the spathe, which consists of a chamber containing the inflorescence (spadix), a tube, and a limb.
— The Beckettii group consists of relatively small plants (up to 40 centimeters high) with lanceolate leaves. Usually, the leaves are colored in brownish-reddish tones of varying intensity, with more or less wavy margins. This group includes C. walkeri (commonly distributed under the name C. lutea), all forms of C. wendtii, C. parva, C. nevillii, C. undulata, and C. x willisii. These plants, living in quiet flowing waters and along banks, prefer moderately lit places. In the aquarium, they also need light and a low water level (no more than 40 centimeters).
— The Griffithii group comprises large plants up to 50 centimeters high with large, broadly cordate leaves. In natural conditions, they grow either in lowlands flooded during the rainy season or in standing water bodies and quiet river bays. In our aquariums, C. purpurea from this group is encountered (known locally as C. griffithii).
— The Cordata group includes beautiful plants with cherry-red leaves such as C. blassii and C. siamensis.
— There are groups consisting of just a single species, such as C. affinis and C. ciliata. All species and varieties of Cryptocoryne are tied to specific native ranges. Only C. ciliata breaks this rule: its two forms (narrow-leaved and broad-leaved) are widespread everywhere Cryptocoryne live—from India to the Philippines. It even settles in river mouths flooded by ocean tides during high water. All the listed Cryptocoryne can live in an aquarium. However, there are some that cannot survive in a submerged state, for example, C. versteegii and C. lingua.
Cultivating Malayan Cryptocoryne (from Sri Lanka) is not difficult if provided with good conditions, which primarily means proper temperature, lighting, water chemistry, and a suitable aquarium substrate. All representatives from tropical equatorial regions require elevated temperatures up to 24-28°C without fluctuations. Light is the second determining factor when growing all Cryptocoryne. Most are shade-tolerant, so moderate lighting is sufficient. Under intense light, plant leaves become covered with algae and curl. Lighting should be 0.4-0.5 W/L. We must pay special attention to the chemical composition of the water. In their native habitats, Cryptocoryne grow in waters with low hardness, high humic acid content, and a substrate containing practically no calcium. They grow best in a soft environment in a shaded location (dH 4-10°, pH 6.5-7.4, with regular weekly replacement of 1/5 to 1/4 of the volume with fresh water). Cryptocoryne from the island of Kalimantan (Borneo) are a different story — these are very problematic plants and are best cultivated outside the aquarium.
Propagation occurs via runners, which can be separated after forming several leaves 4-5 cm long by cutting the creeping shoot on which they formed. To accelerate the propagation of particularly slow-growing species (e.g., Cryptocoryne beckettii, Cryptocoryne retrospiralis, Cryptocoryne undulata), the following method can be tried: all leaves are removed from the plant’s rhizome, and it is set to float on the water surface. After 1-3 weeks, often simultaneously, daughter plants form on it. When they grow several leaves 4-5 cm long, the rhizome is cut, and the plants are planted in the substrate. If only a single plant has formed, it is separated with a small piece of the rhizome, while the remaining part of the rhizome is left floating until the next daughter plant forms.
The plant is susceptible to the so-called “Cryptocoryne rot” (especially in winter), when leaf blades suddenly, sometimes overnight, become soft, glassy, and decompose. In most cases, this happens due to changes in keeping conditions: a sharp change in water parameters during a water change, lighting intensity or spectrum changes, replacement of filter media, addition of chemicals to the water, etc. Sometimes this occurs for no apparent reason. The disease can be transmitted to other aquariums when planting specimens from an infected tank. The exact cause of the disease remains unknown. If leaves begin to decompose, one should try to save the rhizome by performing a water change and removing debris from the substrate. In most cases, the plants recover. Cryptocoryne beckettii, Cryptocoryne wendtii, and Cryptocoryne affinis are particularly susceptible to this disease.
Synonym table for the genus Cryptocoryne.
Anubias lanceolata, gilletii, hastifolia, heterophylla. 
