Aquarium planting

If you're setting up a new aquarium, then you will need to choose between either living plants or plastic substitutes, which are now very realistic in appearance. The inclusion of living plants not only helps to create an attractive natural aquascape however, but it also improves the aquarium environment.

Aquatic plants convert the carbon dioxide produced by the fish to oxygen during daylight. In addition, they use the nitrate produced by the breakdown of the fishes's waste as a fertiliser. Aquaria without living plants are far more likely to be blighted by the growth of unsightly algae as a consequence.

The biggest range of aquarium plants is available by mail-order, from specialist nurseries who advertise in the aquatic magazines or on the internet, but you can find a good selection in local aquatic stores as well. Here you can buy them straight from the water, and transfer them back to an aquarium environment with minimal delay. Their delicate foliage is easily damaged if it is allowed to dry out and so this can be the best option.

Rather than selecting individual plants, you may prefer to purchase a collection instead. These are intended for tanks of specific size, and take a lot of the guesswork out of what is required, provided that you have no strong preferences about the plants you want.

It is always a good idea to wash the plants first in a solution containing an aquarium disinfectant, to avoid introducing any diseases or parasites to the tank which could harm the fish. The planting scheme is very much a matter of personal preference, but careful planning is important, so there will be no need to disturb the plants as they grow.

Planting schemes

As a general guide, taller plants should be situated at the back and around the sides of the tank, with one being used as a centrepiece. By setting plants in small pots, so there is less risk of their roots blocking the slits of the undergravel filter. The pots themselves can then be concealed by gravel.

Smaller plants can occupy the foreground, and some are suitable for growing over rocks and other tank decor. Although they need little actual care, proper lighting conditions will be essential if the plants are to thrive for any length of time in the aquarium. As with garden plants, so some aquatic plants need more light than others.

Inadequate or insufficient lighting remains the major cause of die-back of aquarium plants, which is a shame, because there are now very effective fluorescent lights available to maintain the optimum lighting conditions needed for their growth.

Choosing plants

One of the most versatile plants, whose growth cannot be replicated by plastic substitutes is Java moss (Vesicularia dubyana). This originates from south-eastern Asia, ranging from parts of India eastwards, and including the island of Java. True Java moss will grow well either in an underwater setting, or it can be allowed to spread above the water-level as well, making it useful in a vivarium housing amphibians.

It spreads quite slowly, but its dense growth underwater provides a safe spawning ground for egg-laying species and also offers a retreat for young fry. A mass of Java moss can be easily be held in position on a piece of bogwood or rock by means of a rubber band, until it has established itself here.

Although Java moss prefers soft water, it is very adaptable in terms of its growing requirements. It is not a good idea to include it in a brightly-lit part of the aquarium however, because here, algae will soon develop and choke the dense fronds. The only thing to do under these circumstances is to discard the plant and start again.

The pygmy chain sword plant (Echinodorus tenellus) is a good choice for the front of the aquarium. It has long been popular as an aquarium plant, being easy to cultivate in these surroundings. There can be variations in size however, between the different types. In general, they grow to no more than 5-7.5cm (2-3in) in height, although where these plants are crowded, their pattern of growth is more upright, so they appear taller.

Space out the plants in the foreground at the outset therefore, to create an attractive, low-growing and bright green array of vegetation here. In most cases, pygmy chain sword plants dislike hard water, which makes them ideally suited to an Amazonian tank, featuring fish such as tetras.

Floating plants such as water lettuce (Pistia stratiotes) can be very valuable in the aquarium, offering the fish cover and also screening part of the water surface, creating suitably darkened areas for catfish and others which tend to avoid bright light.

Water lettuce itself will not thrive without good artificial lighting in the aquarium, but it must not come into contact with the droplets of condensation on the cover glass, as with other floating plants. If water drips down persistently on to the plants, it will cause them to turn black and die off.

Under favourable conditions however, it will grow very rapidly, with small plants developing as offshoots on stolons connected to the adult plant, rather like strawberry runners. These stems rot way in due course, leaving the young plants on their own. As they grow, their white roots will turn black - this is quite normal, and not a sign of fungal attack.

Possible problems

Pests tend not to strike aquarium plants as readily as those in the ponds, but snails can prove to be a problem. Dwarf hygrophila (Hygrophilia polysperma) for example is normally a very easy aquatic plant to cultivate in aquarium surroundings, provided that there is not a large population of snails here. They are otherwise likely to strip the leaves in preference to almost other plants growing in the tank.

Cuttings need to be weighed down in groups, and should soon root and grow, to form a dense clump of plants. They can also be arranged in a line, to provide good cover at the back of the aquarium. Although very undemanding in terms of its own growing requirements, dwarf hygrophila will tend to turn the aquarium water more acidic.

Unfortunately however, it is not always possible to grow plants successfully, even under ideal conditions, because certain fish, notably large cichlids, will dig them up, while others may eat them. If you are a keen underwater gardener, you will need to choose your fish accordingly!