Using wood and roots

Wood and roots. For movable plants grown on bogwood ...or on rocks, see "Using plants" in this folder.
"Bogwood" and "Driftwood." Roots, like rocks, anchor the sometimes flimsy compositions offered by plants alone. In a former version of his website, Takashi Amano noted how "pieces of driftwood convey a sense of nature's time-scale — the long cycle of life — death — rebirth — of which we only glimpse fragments."
The real definition of bogwood is wood that has stood for years in an acidic peat bog and has consequently leached out its tannins and has acquired a dark color. Bogwood hasn't rotted, because the low pH of a bog discourages fungal spores and most bacteria. True bogwood is not commercially available.
Corydoras sterbai take momentary refuge in a coconut shell (photo: Anton de Flon)
"Driftwood" from saltwater beaches has been leached in saltwater and bleached by the sun to its familiar gray. Driftwood darkens when it's wet. But in truth most kinds of wood that have naturally weathered for a season or so, away from contact with the earth, which would tend to rot them, can also be used in aquaria. Avoid partly-rotted wood, for the fungi at work in it depend on air, and they will die in water and be decomposed themselves, and the results can overwhelm the aquarium. It is always a good idea to soak any wood in several changes of water before you use it in a fish tank. I don't feel that boiling is strictly required.
Using wood. Weathered fenceposts with holes bored in them will never cut the mustard, even if they've been sandblasted and bolted to a piece of slate. Good pieces of Mopane at the LFS have been split and riven, not sawn; they are full of natural splintery surfaces that will develop rich pastures of biofilm. In water the wood takes on rich mahogany tones, which present handsome contrasts of light and shade. While you're setting the bogwood in place, check the effect under the actual lights you plan to be using. Sometimes a small shift in the wood's position casts a much more telling shadow. Don't forget the possibility of burying part of the wood to give the impression that roots and stumps are protruding from bankside or streambed, for not all the wood found in water has been carried down from upstream.
In a natural stream, sand and gravel silt up behind a long-wedged piece of waterlogged wood. Notice how this works the next time you're checking out a freshwater stream. Recreate this idea when you want to establish a higher level of substrate at the rear of the tank or in a corner; bogwood will help the substrate hold its place, for unsupported gravel slopes always flatten out over time.
With a smallish piece of bogwood, you may want to saw off a section to provide one flat surface where you can firmly attach a suction cup. Then you can fix the piece of wood to the rear glass. This will give an illusion of more depth that you really have. If you do this, you'll want to be sure the juncture between the glass and the wood isn't visible, or folks will see how you cheated. You might not need more than a twist of Java Moss to wrap the joint. I don't like to see bogwood leaning against a side pane, though; it just emphasizes the arbitrary edge. But Takashi Amano has no problem with this, so who am I to be so fussy?
Bogwood can stand upright, as long as it is stable and, just as important, looks stable. Intricate rooty structures, breaking up the aquarium space, foster smaller effective territories, which means you can house more fish. And many freshwater fishes, especially loaches, instinctively like to squeeze into tight spaces. So, don't be limited by the simple arched or branching shapes a single piece of wood can give you. Two or more pieces of root can be fitted together and bound with monofilament to form arched structures and cavelike recesses. The monofilament will be even less visible if you predrill the wood and thread the filament through a small section, rather than wrapping it round the wood.
Twiggy brush. Sometimes you want to have an area broken up by twiggy brush. Nancy Sweeney wrote to me about using twiggy oak branches, "Yes, oak branches. I try to get dried-up ones. I scrape the bark and moss off of them and just dump them in the tank. I've never had a dry one show any 'fungus,' but any sap left in larger pieces may do that. Some of the tiny twigs get knocked off in the scraping but any from pencil size to 50-cent size are ideal. No need to boil or anything. Just make sure they are dry to begin with. I stand some across the back of the tank and have some lying on the bottom."
Links. Aquarium Driftwood is a web source for waterlogged roots, sent wet from Semmes AL and sure to sink for you if you don't let them dry out.  They've been in business for more than a decade. I haven't used these folks myself, but one of the aquaria they illustrate belongs to planted-tank guru Karen Randall. I'm disposed to like any outfit that offers, in addition to their picturesque centerpieces, a driftwood category "Bits and Pieces."
For suitable wood currently available through ebay, search "aquarium wood" in the Pet Supplies section.