Rotala macrandra

by Lynn McMullen
London Aquaria Society April 2001
Aquarticles

When researching the available literature dealing with aquarium plants, often the plants are categorised by growth patterns. Some of those include “roseate” (which defines plants that grow from a common central point, such as Amazon Swords); “opposite leaves” (which includes plants whose leaves grow in pairs on opposite sides of a common stalk, like Hygrophilia polysperma); and plants with “alternate” leaf arrangements (which is when the leaves grow on opposite sides of the stalk, but not exactly at the same point - there is a small space between each leaf). The Rotala macrandra falls into this last category.

This plant has a dense bushy growth pattern under optimum conditions, with many branchlets and thick clusters of leaves, so that it can almost look like an impregnable wall of growth. This is a misleading impression, as the plant can be considered very soft and delicate, never in fact becoming woody or tough. A fish would not become injured on this plant, or even tangled up in long stemmed growths because of the plant’s delicacy. The individual leaves are almost tissue-paper thin. It is common for these leaves to look almost transparent. Because of this characteristic, when the plant is at its fullest and healthiest growth, the rich, red colour of the leaves with the underlying bright emerald green almost makes this plant seem to glow with vibrancy.

It does require some special care to bring about this lush growth. Rotala macrandra requires fairly intense lighting conditions to bring out its best. It will grow under less intense light, but not well, and if the water temperature is set higher than 82 degrees Fahrenheit, the plant is likely to brown off and dissolve. Generally, this plant will do well between 65 degrees and 78 degrees, which should serve the majority of freshwater aquarists.

Because of its delicate nature, including Rotala macrandra with plant-grazing fishes is not recommended, unless intended to be a very expensive food item. Occasionally, a fish such as a clown loach will peck at the leaves in hope of a snail or stray particle of food, and develop a taste for the plant itself, then continue to eat it with dedication, (stalks included) right down to the substrate. This plant is also STRICTLY aquatic. If it dries, it dies.

Rotala macrandra can grow quite tall, achieving a height of 24 inches, but if too thickly planted at the substrate, the lower portions of the stalk will suffer a leaf die-off from lack of light, causing the plant to develop a weedy “scraggly” look. Leave about 2 inches between small groups of stems when planting (with 2 or 3 stems per group), and this should thwart the weedy look from occurring.

Propagation is most easily accomplished by cuttings. When the plant is becoming too tall, or otherwise requires pruning, sections may be cut from the parent plant, at about 4-6 inches long. If all your plants are to be pruned at once, cut off the bottom sections and replant only the top sections for the best appearance, The lower cuttings may be then used in a “nursery” tank to start new plants, where appearance is of no concern.

In order to maintain the ripe red colour of rotala macrandra, an iron-rich fertiliser will need to be used. Ensure that the fertiliser chosen is designed for aquarium use, as “land” fertilisers may contain too many of the incorrect elements and cause an algae explosion, or even death to the fishes. Also, be cautious using medications for fishes in a tank with plants, as many of them will cure your fish, but kill your plants, particularly those containing copper-based remedies. Some antibiotics may also be quite harmful to the plants, dependent upon the dosages being used. To be on the safe side, remove the plants during medication cycles to an alternative location.

This plant can be a real showpiece with a little effort and care. If you can find it .