What can I decorate my tank with?
Any rocks, gravel, plants and ornaments you buy from a reputable aquarium store are safe to put in the tank, but be careful of adding any rocks you collect yourself. Slate, quartz, granite and silica-based sand stone are suitable, limestone (including shells and coral skeletons), marble and rocks containing metallic veins are generally not. Care must be taken with rocks from the garden as these may have absorbed pesticides etc. Soak them for several weeks to make sure any contaminants have leached out before using them in aquaria. Glass, plastic, fired ceramics and polyresin ornaments are ok, so long as they have not been painted (or if you know the paint is non-toxic). Wood is generally not suitable, since many types of wood will leach out sap that may be toxic, and is, in any case, very messy. Aquarium driftwood is not harmful, but often leaches tannins that turn the water a murky yellow, even for months after its addition. Live plants can also be used to decorate the aquarium, and can be beneficial when growing well, but they can be hard to grow and are not essential. Treat plants collected from natural waterways with extreme caution. They will often not adapt to aquariums and so die off, depleting water quality, or they may harbour disease organisms or pests.
What kind of gravel should I use?
This is largely a matter of taste, and many suitable gravels are available. A coarse sand or fine pebble with a grain size of 2 – 4 mm is generally best. These finer gravels make it easier to establish plants, and are cleaner, since food particles cannot fall between the grains. Slightly coarser gravels (up to 6mm grain size) are also suitable, although you may need a thicker layer to anchor plants. Larger pebbles, glass marbles, “crystals” (actually coloured glass), and coloured gravels are also safe to use, but exercise caution: these coarser substrates can trap uneaten food particles between the grains, leading to pollution of the aquarium, and they are also unsuitable for growing live plants.
Do I need a light?
Fish themselves do not need artificial lighting in an aquarium, however, lighting is desirable for a number of reasons. Firstly, lighting is necessary if you want to grow live plants. Indirect sunlight or room lighting does not provide sufficient light for aquarium plants, and direct sunlight will favour the growth of algae. Secondly, the appearance of an aquarium is greatly improved by having proper aquarium lighting. Aquarium tubes not only have a suitable spectrum for growing plants, but also show off the colours of the fish to their best advantage.
What kind of lighting is best?
Fluorescent lighting is nearly always the best for aquariums. Incandescent globes are sometimes used, but the spectrum of light these produce is not ideal for plants or to show off the fish. Also, they produce a lot of heat, and are not very energy efficient, costing more in the long run despite their initially cheaper price. Fluorescent tubes produce relatively little heat, are energy efficient, and proper aquarium tubes are available. Standard household tubes generally have a spectrum with too much yellow for aquarium use, these promote algae and give the aquarium a murky appearance. Invest in proper aquarium tubes for the best results. Aquarium tubes come in a number of varieties. Standard aquarium tubes (eg Aquaglo) are usually of moderate brightness and have a spectrum with mostly red and blue light (although this appears a warm white to the human eye). These give a soft, natural light that shows off the colours of most fish very well, and is suitable for most aquatic plants. These tubes are suitable for nearly all aquariums. If a brighter light is desired, eg in a very deep tank or in marine aquariums, higher intensity tubes (eg Powerglo) are available. As well as being brighter, these have a slightly crisper, cooler look. These also bring out the colours of the fish and are suitable for plants. Usually they are a little more expensive than standard tubes, but are equally suitable, if not even more desirable. Even brighter again are compact fluorescents. Like other fluorescent tubes they are cool running and economical Light fittings for compact fluorescents are slightly more expensive than for standard fluorescents, but the tubes themselves cost about the same. Various spectra are available, but bright white is the best in most cases – this has a similar spectrum to a high intensity aquarium fluorescent. Actinic (blue) compact fluorescents are also available. Actinic tubes have a large amount of blue in their spectrum. The main use of these tubes is in marine aquariums, where they are used to complement other tubes to replicate the blue-ish light found on coral reefs. In any aquarium they can be used to create a dawn to dusk effect. The actinic, with it’s dim, blue light, is placed on a separate timer to come on an hour or so before the other aquarium lights, and turn off an hour or so after the main lights go out. Actinics are not suitable as the sole light source for an aquarium. Tri-phosphor tubes are sometimes used in aquariums. These are a bright tube with little yellow in the spectrum and so give a nice appearance at relatively low cost. However, their spectrum is not ideal and they tend to promote the growth of undesirable algae. Other lighting types are mercury vapour and metal halide. These lights are considerably brighter than even compact fluorescents, but are more expensive. They also use more power and produce more heat. The main application for these lighting systems are in very deep planted tanks or for very serious reef set ups.
Should I have live plants?
There is no necessity to have live plants in your aquarium, but they are desirable in many cases. If you can grow lush and healthy plants in your aquarium, they are an invaluable aid in maintaining water quality. However, in many cases the plants will be eaten by the fish with no real benefit obtained, or they will die off and rot, depleting water quality. If your plants are not growing, then there is little point in constantly replacing them, except for their asthetic value. Additionally, there is nothing wrong with plastic or silk plants, and many are very realistic in their appearance. In fact, artificial plants of either kind provide additional surface area for filtration bacteria, and so having artificial plants may be even more beneficial than having live plants that are dying off. Rotting plant matter introduces extra waste product into the aquarium, and this is certainly not desirable. If you have plant eating species in your aquarium, there is nothing that can be done to change their habits. Giving a number of feeds a day may stop omnivorous and scavenging fish from nibbling at plants, but true herbivores will graze on any available plants no matter what else they are offered. Although it is not detrimental to the fish or to the aquarium, it can be expensive to continuously replace plants that are being eaten, and there really is no need. It is best to feed herbivores a diet high in spirulina rather than relying on them eating your plants to satisfy their needs. However, if you have an aquarium light and keep fish that do not eat plants, it is a good idea to add live plants. Live plants remove nitrogenous waste products and so improve water quality. Many fish will also be less stressed and less prone to disease in a heavily-planted aquarium.
How do I get live plants to grow?
While plants are desirable, many are much harder to grow than might be expected. Some are hardier than others, and will do well with relatively little care, others need very specific conditions. Most need proper aquarium lighting as a minimum. The only plant that will survive in low light (ie without proper aquarium lighting) is Vallis (thin: Vallisneria spiralis or giant: V. gigantea). Other hardy varieties such as Stricta (Hygrophila stricta), Wisteria (Hygrophila difformis), Hydrilla (Hydrilla verticalla) and Cabomba (Cabomba aquatica) need proper aquarium lighting, but little more. Cabomba and Hydrilla will grow floating in the water (or can be planted), while the other varieties need a one to two inch layer of gravel in which to establish their root system. For best growth, regular water changes are necessary. Although plants use the waste products produced by the fish, if nitrate concentration becomes too high, this can actually damage the plants, and high nitrates favour algae which can grow on and choke the plants. These hardy varieties will grow even better with proper aquarium fertilisation (these fertilisers do not contain nitrate and phosphate like garden fertilisers!). The finer leaved Cabomba and Hydrilla may be hard to grow if your fish nibble on plants. Stricta and Wisteria are more resistant to being eaten. Most other plant varieties need extra fertilisation in order to do well. A number of plant fertilisers are available, including substrate fertiliser, slow release tablets, liquid fertilisers and daily fertilisers. The best system to use is a combination of substrate, slow-release, and daily fertilisers. If only one is used alone, daily drops give the greatest benefit of these three. Fertilisation with carbon dioxide is also used with good results, promoting faster growth and better plant development, but adding CO2 does little if the plants do not have all the other nutrients and trace elements they require. Extra lighting may be needed for some varieties, particularly red coloured plants, and extra light intensity will benefit all varieties. It is best to use either compact fluorescent lighting or two sets of standard aquarium tubes rather than a single high-intensity tube, but a single high intensity tube is better than a single standard tube. The duration of lighting should be around twelve hours, less where there are few plants or very bright lights, more where there are more plants or less intense lighting. Any more than fourteen hours of light will only promote the growth of algae. For more information on growing plants, see our article on planted aquaria.