Spider Wood in Aquascaping: Selection, Prep and Creative Uses

What Is Spider Wood?
Characteristics of Spider Wood
Choosing the Right Pieces
Preparation: Soaking, Boiling and Waterlogging
Tannins: Friend or Foe?
Anchoring Spider Wood in Your Aquarium
Creative Uses in Aquascaping
Combining with Other Hardscape
Attaching Moss and Plants to Spider Wood
Frequently Asked Questions

What Is Spider Wood?

Spider wood, also known as azalea root or rhododendron root, is a type of driftwood prized in aquascaping for its intricate, branching structure. It is harvested from the root systems of azalea and rhododendron shrubs, which produce dense, tangled networks of thin branches that fan outward in organic, web-like patterns — hence the name “spider wood.” This guide sits inside our broader Planted Tank Complete Hub reference.

In the aquascaping world, spider wood has become one of the most popular hardscape materials alongside Manzanita wood, Malaysian driftwood and bog wood. Its natural beauty, versatility and relatively affordable price make it a favourite among hobbyists in Singapore, from beginners creating their first aquascape to experienced competitors designing contest entries.

Characteristics of Spider Wood

Several qualities make spider wood uniquely suited to aquascaping:

Branching structure: The defining feature. Spider wood branches in multiple directions, creating complex, three-dimensional shapes that mimic tree roots, fallen trees and forest undergrowth. No two pieces are alike.
Organic shapes: Unlike heavier driftwoods that tend to be chunky and solid, spider wood has a delicate, flowing quality. The branches taper naturally, creating visual movement and a sense of dynamism in the aquascape.
Lightweight: Spider wood is significantly lighter than Malaysian driftwood or ironwood. This makes it easier to handle and position but also means it floats when first introduced to water — a challenge that requires patience to overcome.
Warm colour: Dry spider wood ranges from golden brown to reddish brown. Submerged, it darkens to a rich, warm brown that contrasts beautifully with green plants and grey stone.
Relatively affordable: Compared to premium driftwoods like Manzanita or Japanese Sumida wood, spider wood is moderately priced and readily available from aquarium shops across Singapore.

Choosing the Right Pieces

Selecting spider wood is one of the most enjoyable parts of planning an aquascape. Visit the shop in person rather than ordering online — you need to examine the three-dimensional shape of each piece to judge how it will look in your tank.

When selecting spider wood, look for:

Interesting branching: Choose pieces with branches that extend in different directions and at varied angles. The best pieces have a central mass with branches radiating outward, creating depth and visual interest from multiple viewing angles.
Scale appropriate to your tank: A massive, heavily branched piece that dominates a 30cm nano tank looks cluttered, while a small, sparse piece in a 120cm tank looks lost. Hold the wood next to your tank dimensions (or bring a measuring tape) to gauge scale.
Natural taper: Branches that taper from thick to thin look more natural and elegant than branches of uniform thickness. Good spider wood narrows gracefully towards the tips.
Character features: Knots, bends, split branches and unusual curves add character and realism. Perfectly straight pieces are less interesting than ones with natural quirks.
Attachment points: Consider where you might attach moss, Bucephalandra or Anubias. Textured bark, crevices and branch junctions are ideal spots for tying or gluing plants.

Buy more than you think you need. Having several pieces to combine gives you flexibility during layout. Most successful aquascapes use two to four pieces of spider wood arranged to look like a single, cohesive structure.

Preparation: Soaking, Boiling and Waterlogging

Spider wood requires preparation before it can be used in your aquarium. Skipping this step leads to floating wood, excessively tinted water and potential biofilm issues.

Soaking

Submerge the spider wood in a bucket, tub or spare tank filled with water. Weight it down with rocks or bricks to keep it submerged. Soak for one to two weeks, changing the water every two to three days. This serves two purposes: it begins waterlogging the wood (so it eventually sinks) and leaches out tannins that would otherwise discolour your aquarium water.

Spider wood is slow to waterlog due to its low density. Thin branches may become waterlogged within a week, but the thicker central mass can take two to four weeks or even longer. Patience is required.

Boiling

If the pieces are small enough, boiling accelerates the preparation process dramatically. Boil the spider wood for one to two hours in a large pot (use a pot dedicated to this purpose — do not use your cooking pots). Boiling achieves three things simultaneously: it sterilises the wood, accelerates tannin release and speeds up waterlogging by forcing water into the wood’s pore structure. After boiling, the wood may still float but will waterlog much faster during subsequent soaking.

Note that boiling can soften very thin branches and may cause some fragile tips to break off. Handle boiled wood gently.

Scrubbing

After soaking or boiling, scrub the wood with a stiff brush to remove any loose bark, dirt and debris. This reduces the amount of organic material that enters your aquarium and minimises the initial biofilm bloom that commonly occurs when new wood is submerged.

Tannins: Friend or Foe?

Spider wood releases tannins — naturally occurring organic compounds that tint the water a yellowish to amber-brown colour. This effect divides hobbyists:

The Case for Tannins

Tannins create a “blackwater” aesthetic that mimics the natural environment of many popular aquarium fish, including tetras, rasboras, bettas and discus. Blackwater conditions lower pH slightly, provide mild antibacterial properties and create a dramatic, moody atmosphere. Many aquascapers deliberately cultivate tannin-stained water for its natural beauty.

The Case Against Tannins

For hobbyists who want crystal-clear water to showcase their aquascape, green plants and colourful fish, tannin staining is unwanted. Yellow-tinted water can make an otherwise stunning tank look dingy, particularly under white LED lighting.

Removing Tannins

If you want to minimise tannin staining:

Extended pre-soaking: The longer you soak the wood before adding it to your tank, the less tannin remains to leach.
Activated carbon: Running activated carbon in your filter absorbs tannins from the water. Replace the carbon every two to four weeks as it becomes saturated. This is the most effective method for maintaining clarity after the wood is in the tank.
Purigen: Seachem Purigen is a synthetic adsorbent that removes tannins, discolouration and organic waste from the water. It is rechargeable (soak in bleach, rinse, reuse) and more effective than standard activated carbon.
Water changes: Regular partial water changes dilute tannins. Combined with carbon or Purigen, this keeps the water clear within days of adding new wood.

Anchoring Spider Wood in Your Aquarium

Because spider wood floats for an extended period, you need a strategy to keep it in place:

Screw to a stone base: Drill a hole through the base of the spider wood and through a flat rock. Secure them together with a stainless steel screw and nut (use only stainless steel — other metals corrode). Bury the stone under the substrate. This is the most reliable method and provides a permanent anchor.
Glue to rock: Use cyanoacrylate (superglue) gel to bond the spider wood directly to a heavy rock. Apply a generous amount and hold firmly for 60 seconds. The bond may not be as strong as a screw, but it works well for lighter pieces.
Wedge between rocks: If your aquascape includes a stone arrangement, wedge the base of the spider wood between rocks so the weight of the stones holds it down. This is less permanent but allows easier repositioning.
Wait for waterlogging: If you have the patience, simply weight the wood down in the tank with rocks or clamps and wait for it to become waterlogged enough to stay put on its own. This can take two to six weeks depending on the size and density of the piece.

Creative Uses in Aquascaping

Spider wood’s branching structure lends itself to several iconic aquascaping compositions:

Bonsai Tree

Perhaps the most popular use of spider wood is creating a miniature underwater bonsai tree. Select a piece with a thick base and upward-spreading branches, mount it on a rock (the “root system”), and attach moss or Riccardia to the branch tips to create a “canopy.” The result is a captivating tree-in-a-tank effect that draws the eye and creates a focal point for the aquascape.

Root System

Turn a piece of spider wood upside down so the branches fan downward, mimicking the exposed root system of a tree growing on a riverbank. Position it at the edge of the hardscape as if the roots are reaching into the water. Combine with stem plants growing above to suggest the tree’s canopy.

Overhang

Mount spider wood so that branches extend horizontally over an open foreground area. The overhanging branches create a canopy effect, casting natural shadows on the substrate below. Attach ferns, Bucephalandra or Anubias to the branches for added realism. Fish swimming beneath the overhang recreate the feeling of a natural waterway beneath overhanging vegetation.

Fallen Tree

Lay a long piece of spider wood horizontally across the tank, as if a tree has fallen into a stream. The branches reaching upward and to the sides create a natural-looking obstacle that fish swim around and through. This layout works particularly well in biotope aquascapes representing Southeast Asian stream habitats.

Combining with Other Hardscape

Spider wood pairs beautifully with stone. Common combinations include:

Dragon stone: The textured, earthy appearance of dragon stone complements spider wood’s organic branching. Together, they create a natural landscape of rock and root.
Seiryu stone: The blue-grey tones of Seiryu stone contrast dramatically with spider wood’s warm brown, creating visual tension and depth.
River pebbles: Small, rounded pebbles scattered around the base of spider wood suggest a riverbed, enhancing the natural aesthetic.

When combining spider wood with stone, establish the stone layout first, then add the wood. The heavier stone serves as the structural foundation of the aquascape, with spider wood adding organic detail and visual complexity on top.

Attaching Moss and Plants to Spider Wood

Spider wood’s rough bark and branching structure make it ideal for attaching epiphytic plants:

Moss: Wrap thin layers of Java moss, Christmas moss or flame moss around branches using cotton thread or fishing line. Within four to six weeks, the moss will attach and the thread (if cotton) will dissolve.
Bucephalandra: Glue Bucephalandra rhizomes to the wood using cyanoacrylate gel. Bucephalandra grows slowly and attaches firmly, eventually covering the glue point entirely.
Anubias: Tie or glue Anubias rhizomes to branch junctions or the main trunk. Small varieties like Anubias nana petite are ideal for spider wood’s scale.
Java fern: Attach to larger branches or the central mass. Java fern’s dark green fronds provide excellent contrast against the warm-toned wood.

For more driftwood options and preparation techniques, see our guide on the best driftwood for aquascaping. Drop by Gensou at 5 Everton Park to browse our selection of spider wood — with over 20 years of aquascaping experience, we can help you choose pieces that work for your tank dimensions and layout vision. Our Java moss guide covers the most popular plant for dressing spider wood.

Frequently Asked Questions

How long does spider wood take to sink?

Spider wood is one of the slowest-sinking driftwoods due to its low density. Thin branches may waterlog within one to two weeks, but the thicker main body can take two to six weeks of continuous submersion. Boiling before soaking accelerates the process. Many hobbyists simply anchor the wood to a stone rather than waiting for it to sink naturally.

Will spider wood lower my aquarium pH?

Spider wood releases tannins that can lower pH slightly (by 0.2-0.5 points in soft water). In Singapore, where PUB tap water has a pH of approximately 7.5-8.0 and moderate hardness, the buffering capacity of the water limits the pH-lowering effect. If you run active substrate that also lowers pH, the combined effect may be more significant. Monitor pH during the first few weeks after adding spider wood.

Is the white biofilm on spider wood harmful?

The white, fuzzy biofilm that commonly appears on new spider wood within the first one to four weeks is a bacterial film feeding on organic compounds leaching from the wood. It is completely harmless to fish and invertebrates. Shrimp, snails and Otocinclus will eagerly eat it. The biofilm disappears naturally once the wood’s easily digestible organics are consumed. Do not mistake it for fungal infection — it is a normal and temporary phenomenon.

Can I reuse spider wood from a previous aquascape?

Yes, spider wood can be reused indefinitely. When breaking down a tank, remove the wood, scrub off any algae or dead plant matter, and let it dry completely. Store it in a dry location. When you are ready to use it again, it will need to be re-soaked as it will float again after drying out. However, the tannin release will be much less the second time around.

Your Cart