To create a healthy environment for your fish, it is important to provide them with plenty of hiding places. Fish that are housed in a relatively bare aquarium will often become stressed and unhealthy. In most cases, decor will consist of elements such as rocks, wood, plants and artificial decor. There is a massive choice of decor available for the aquarium that can be purchased from aquatic stores and garden centres although some are more suitable than others.

Rocks
Rocks and substrates that are intended for marine aquariums can alter the pH of the water, which can be damaging to some freshwater fish species. Such items should be labeled at the place of purchase although they often are not. The only way to be sure is to check with a good retailer when you are purchasing decor. Rocks such as chalk, limestone, marble and tufa rock are all unsuitable. Safe rocks to use in the aquarium include coal, basalt, flint, granite, sandstone, quartz, slate and lava rock. Be careful when using larger rocks as a badly positioned piece can easily fall. Large rockscapes should be constructed with care and with good advice.

Bogwood
Bogwood is a popular form of decor for the aquarium and creates a pleasing natural appearance. Bogwood is a form of wood which has been naturally soaked and preserved for many years and should not rot in the aquarium. Other sources of wood should never be used in the aquarium unless they have been specifically treated for aquarium use. Bamboo is often seen in some displays although this wood must be prepared and varnished with a clear polyurethane varnish before use. Many types of bogwood are available and often come under different names such as jati, mopani, or twisted roots. Over time bogwood releases tannic and humic acids into the aquarium. For most fish this is not harmful, and often beneficial, but it does lower the waters pH and hardness levels. The tannic acids also produce a yellow-brown tea like colour in the water, which can be removed by the use of special chemical medias

Artificial decor
Synthetic or artificial decor is available in many forms ranging from fluorescent skulls to natural wood and rock re-creations. Artificial decor items should only be bought from aquatic retailers where they are designed specifically for the aquarium. Artificial decor is often a little expensive but has many benefits. Artificial decor is easy to remove and clean, is inert so will not affect the water, and comes in forms specifically made to hide equipment or provide hiding spots.

Substrate
The substrate (gravel) for the aquarium floor should be chosen with care. If you wish to keep live plants then a fine, lime-free substrate or a mix of specialised substrates may be required. For most aquariums any inert substrate will do. Coloured substrates are sometimes used in aquariums, although the effect is either loved or hated and may look rather un-natural. Sand substrates are also available and can be used to good effect in many aquariums although sand does require more maintenance than gravel substrates. Any substrates that are designed for marine aquariums should not be used; these are often rich in calcium and will alter the water chemistry. It is worth noting that most fish prefer a dark or natural coloured substrate, and dark or subtle substrates also show up the fish's colours better.

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