Collect Your Own Decor

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Setting up aquariums can be a costly business and aquarium decor is usually sold at a premium price, so is collecting your own rocks and wood a good alternative? If you follow a few essential rules you can aquascape your tank for next to nothing, but get it wrong and you could wipe out all your livestock.

Aquarium bogwood

The benefits of buying from a fish shop

The rocks, wood, and gravel sold by your aquatic retailer will be made for aquarium use, so you know they are safe to use and free from harmful contaminants. If you take a slightly cheaper option and opt for similar looking gravels or rocks from builders yards or garden centres, there may be a danger of metal ores mixed in with the stones, which will leach into the water and may be toxic. There may also be some non-inert or hardness raising elements that will cause problems with pH and hardness levels. Gravels and substrates should always be bought from an aquatic retailer, but rocks and other decor can be collected for free with a little care.

Collecting rocks and stones

To use collected rocks you need to have a rough idea of the type of rock you are using. Rocks like chalk, marble, limestone, or tufa (often sold for marine tanks) will all dramatically raise the waters hardness and are unsuitable. Safe inert rocks include flint, slate, basalt, granite, sandstone, quartz, or even coal. Rocks can be collected from anywhere but you can never be sure of what they may have come into contact with. Rocks from a garden may have been sprayed with weed killer for example, or rocks from fields may have pesticide residues. A safer bet is to collect rocks from in or near a healthy body of water such as a clear stream, river, or shore; these will have already been soaked to remove toxins. There is the risk of introducing nasty water-based problems such as algae's, parasites, or other diseases. To prevent this give the rocks a thorough wash, and if you really want to be extra safe a quick boil. Avoid any rocks that have any veins, or lines of colour, as these may be metal ores and could be toxic - the only exception is quartz veins, which will be white in colour. Natural lava rock should also be avoided for the same reasons, as they tend to contain large amounts of metals and toxins.


Aquarium bogwood is very expensive, but this is because it has been collected, cleaned, treated, and shipped long distances, and will be known to be aquarium safe. Picking up any old bit of wood you find and putting it straight in a tank without prior treatment is a sure-fire way to have serious problems. Bogwood can be used in aquariums because it has been waterlogged for hundreds of years and preserved by peat, recently dead wood will simply rot away in normal conditions underwater. Any wood you collect must have therefore been exposed to waterlogged conditions for some time, so woods from fen ditches and riverbanks are usually best. Once collected the wood will need to be thoroughly cleaned to remove any soil and then soaked for several weeks, ideally with some activated carbon in the water, to leach out any impurities. Finally, it is always best to give the wood a long boil to kill off any lurking nasties before it goes in the tank. Boiling should be done for at least an hour, if not several hours, and will help the wood to sink by driving air out during the boil.

If you are keeping any suckermouth catfish, they will graze on woods so avoid very soft woods that your catfish will quickly break apart and leave a mess of tiny shavings in the aquarium.

Driftwood and brushwood

Like bogwood, driftwoods from beaches are already waterlogged and less prone to rotting, but avoid anything collected from a populated area as it may have been near a sewage outlet, and give plenty of soaking time to remove salts from the wood. As mentioned, recently dead wood will tend to rot-away and is best avoided, but it is possible to use thinner branches of dead woods, or brushwood. The first thing to do is make sure the wood actually is dead and dry, and you can do this by picking the thickest and lowest part of the branch and breaking it. If it bends, producing stretched fibres or green parts, it is not fully dead and may cause problems, if it snaps fully and is dry inside it is fine. The branches can then be rinsed, soaked, and again if you want to be extra safe, boiled. Only use the thin branches, ideally those less than 5mm, anything bigger may leach sap.


A very commonly used and effective display wood is bamboo, which can be picked up from any garden centre and with a little preconditioning, is safe to use in an aquarium. Thinner bamboo canes up to a centimetre can be rinsed and placed straight in the tank, larger diameter pieces will need some preparation. The first thing to do is remove the film-like coating which can be found inside the bamboo sections, the wood can then be soaked for several weeks. The insides of Bamboo tend to fungus and cause cloudy water, so the soaking process will work through this. Bamboo is very buoyant so it will need to be siliconed to heavy rocks as weights or wedged in place. Over time bamboo will also rot away but you can delay this process by coating the bamboo with a clear polyurethane varnish before it goes in the tank.

Cork Bark

Tree bark can be used to make excellent decorative aquarium items or backgrounds, but like bamboo it is very buoyant so it may need to be fixed into position or weighted down. Also like bamboo, it may rot over time so if you are fixing it, bear in mind it may need to be taken out at a later date. Never strip bark away from a living tree as it may damage the tree, and will probably also contain lots of nasties. Instead use bark from a dead tree or even better, get some from a reptile supplier. If you use collected bark, the usual rules apply so soak and then boil to aid sinking and to remove toxins and bugs.

Leaf litter

It is possible to use dead leaves as an effective decoration in the aquarium, some leaves in fact, like Indian Almond Leaves, are even used for their anti-bacterial and health boosting properties to aquarium fish. For collecting in this country, oak leaves are best since they do not break down as quick and release fewer nutrients. The leaves will need to be fully dried and then briefly pre-soaked before use. Leaves will always break down over time and the debris will need to be siphoned away, and they will also have a water-softening effect, but they do seem to be enjoyed by many species of fish.


Collecting shells from beaches can be good fun, and you can also pick up some nice decorative items for your aquarium. Whilst shells are mainly calcium and will raise the waters hardness, a couple of shells will make little difference, especially if you also have wood in the same tank. Make sure your shells are empty and give them a rinse out before use. If you buy shells for the aquarium, see if you can find out where they come from, as it is still possible to buy shells that have been collected through environmentally destructive means.

Other objects for aquarium decorations

As you can tell, we have focussed on naturally occurring mundane objects like rocks, wood, and leaves, but what about more decorative items which can be purchased from craft stores or created from other objects? Most items, whether made from wood, metals, glass, plastics or whatever will have some kinds of chemicals used in their production. Glues, varnishes, preserves, paint, or resins can all be toxic in an aquarium so if a human made it, it's probably not safe. For decorative items, stick to those sold specifically for aquariums and follow the simple rule of 'if your not sure, don't try it'.

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