Dwarf Lilies (Nymphaea nouchali)
Nymphaea nouchali is an extremely hardy plant and very easy to grow. It is an excellent choice for aquarist beginners who want to create a planted tank as it grows robustly and requires little maintenance (at least initially).
Also known by several taxonomic synonyms (most commonly as Nymphaea stellata), the species is considered by some botanists as a variant of Nymphaea caerulea (blue Egyptian lotus). Apart from dwarf water lily, this plant is also known by several other common names such as star lotus, blue lotus, blue star water lily, red and blue water lily, and manel flower.
The dwarf water lily is an Indian plant native to south-central Asia (India, Bangladesh, and Sri Lanka) and is the national flower of the countries of Bangladesh in the east in the Ganges-Brahmaputra river delta and further south in Sri Lanka on the island of Ceylon. Its presence has also been reported to the west in Afghanistan, throughout southeast Asia, and as far east as Taiwan on the island of Formosa.
Nymphaea nouchali is found in many places where it is not native and is considered a pest weed: Mississippi river system, coastal US, central America, southeastern Brazil, Uruguay, southern Africa, and north and eastern Australia. Despite its beauty, the dwarf water lily is in the top ten list of invasive bad guys.
The dwarf water lily is typically found growing in soft, slightly acidic water of slow-moving river estuaries, marshes, and bodies of open freshwater. Nymphaea nouchali is a day-blooming angiosperm in the Nyphaeaceae displaying triangular leaves that are green, red, and sometimes pink that bloom at different growth stages.
Broad attractive leaves of dwarf water lily differ from other plant shapes and provide interesting pattern contrast. The plants will produce spade-shaped leaves submerged and lily pads on the water surface.
Dwarf water lilies are moderate to aggressive in their growth pattern and will consume nitrate and phosphate growth nutrients from the tank, providing a more chemically-sound environment for animal life in the aquarium.
Certain species of fish that prefer secrecy when eating will forage in the open under the shadows of this plant. A few examples are Microglanis iheringi (bumblebee catfish) and Apteronotus albifrons (black ghost knifefish) which will forage out in the open under lily pad shadows, allowing them to be observed in a low stress environment. Dwarf suckerfish, such as otto cats (Ottocinclus affinis) will readily groom dwarf water lilies of algae and improve plant growth by allowing better light access. Some fish should not be hosted with dwarf water lily if you are unprepared for plant damage such as herbivores like silver dollar fish (Metynnis spp.) and larger species of cichlids.
How to Care for Dwarf Lilies
Dwarf water lilies, owing to their native climate, thrive well with bright light and the addition of carbon dioxide to the water. Short of a carbon dioxide injection system, they will grow well as long as they are provided with enough light and a source of nitrates and phosphates.
Fish and invertebrate waste in the tank will usually provide enough of these nutrients, however, a supplement of fertilizer will be necessary if the plants do not seem to thrive under the conditions of the tank. Since Nymphaea nouchali tends to reproduce by vegetative propagation in aquarium conditions through the production of lateral stolons that extend themselves across the surface of the substrate, the use of fertilizer tablets is extremely helpful and recommended.
Place tablets nested shallowly in the substrate along the extended stolons, which will have the appearance of lateral stems. Nymphaea nouchali will readily take up the nutrients from the tablets before they disperse chemicals to the rest of the tank, so if you have other plants, you may need to provide a liquid fertilizer as well to care for them.
After the addition of any fertilizers to the aquarium, be sure to perform a set of water tests for pH, nitrates, and phosphates as well as for water hardness.
Be sure to purchase fertilizer tablets that include chelated iron, as this is a necessary growth nutrient for dwarf water lilies. You should not expect to see dwarf water lilies flower under aquarium conditions since there is a lack of both seasonal cues for inflorescence and a lack of access to necessary pollinators.
Growths reaching the water surface will produce lily pads where flowers would appear if the conditions are favorable. Lily pads will eventually grow to convergence and will require you to prune them to keep them from preventing light access to deeper levels of the aquarium.
If the lower trunk of the dwarf water lily has access to light, it will continue to produce submerged fronds and provide good cover, as well as an aesthetic contribution, to your tank. Pruning should be performed with sharp scissors and the cuts should be made at the stem origin if attempting to remove lily pads.
Leaves will eventually become covered with algae and should also be pruned to prevent decay and spurring on of algal growth, which can lead to an algal bloom (something you should avoid, if at all possible, since algae will gradually outcompete your plants for dissolved oxygen).
Dwarf water lilies prefer soft water rich in nutrients at temperatures of 22-28°C. The plants also prefer a range of pH from 5-8, which is very compatible with many other aquatic plants and fish life.
When establishing your new dwarf water lilies, which are often received as just a bulb, seat them in the substrate half-way in to prevent any bulb decay. If you find that the bulbs are buoyant, first soak them in clean, dechlorinated water until they submerge before attempting to plant them in the tank.
New growths can also be transplanted to new locations in the aquarium or transferred to another tank, so long as they are allowed to first establish roots in the substrate. This will indicate that the new plants are able to sustain themselves and no longer rely on the parent plant.
Nymphaea nouchali occasionally sheds its leaves, which is completely normal, however, these leaves should be removed from the tank before decay sets in. Failure to do so will create conditions favoring algal growth and an eventual algal bloom problem.