How to Fix Water Mould on Driftwood in Your Aquarium
You have just added a beautiful piece of driftwood to your aquascape, and within days a fuzzy white film blankets its surface. Do not panic — this is water mould, and it is one of the most common issues new driftwood introduces to an aquarium. Knowing how to fix water mould driftwood aquarium problems quickly saves you weeks of frustration. This guide from Gensou Aquascaping at 5 Everton Park, Singapore, explains what causes the growth, how to remove it, and how to prevent recurrence. Nearly every aquascaper encounters this at least once.
What Is Water Mould?
The white, cotton-like growth on driftwood is typically a biofilm composed of saprophytic fungi and bacteria — not true mould in the household sense. These organisms feed on organic compounds leaching from the wood, particularly sugars and tannins that dissolve as the wood saturates. It is completely harmless to fish and plants. The biofilm appears most aggressively on newly submerged wood and can show up on both properly prepared and unprepared pieces. Some wood types — spider wood and manzanita in particular — produce heavier biofilm than denser options like Malaysian driftwood or ironwood.
Manual Removal
The most straightforward approach is physical removal. Use a soft toothbrush or small brush to scrub the affected surfaces during a water change. Remove as much as you can, siphon out the loosened material, and replace the water. This will not eliminate the biofilm permanently in one session — it typically regrows within days as the wood continues leaching organics. However, each cycle produces less growth as the available nutrients in the wood deplete. Most driftwood stops producing biofilm within three to six weeks of submersion.
Biological Control
Nature’s cleaners handle water mould more effectively than manual scrubbing. Amano shrimp (Caridina multidentata) devour biofilm enthusiastically — a group of five to ten can strip a medium piece of driftwood clean overnight. Nerite snails graze it steadily, and bristlenose plecos rasp it off as part of their general surface cleaning. Cherry shrimp and other Neocaridina species also consume it, though less aggressively than amano shrimp. In Singapore, amano shrimp are widely available at $1–$2 each from shops around Serangoon North and online on Shopee.
Boiling and Soaking Before Use
Prevention starts before the wood enters your tank. Boiling driftwood for one to two hours extracts a significant portion of the organic compounds that feed biofilm. Use a large stockpot and change the water between boiling sessions if it turns deeply amber. For pieces too large to boil, soak in a bucket or tub of warm water for one to two weeks, changing the water every few days. This pre-soaking method is particularly practical in Singapore, where large stockpots may not accommodate the dramatic spider wood branches popular in aquascaping.
Hydrogen Peroxide Treatment
A targeted hydrogen peroxide (H2O2) application kills biofilm on contact. Use 3% pharmacy-grade H2O2 — the standard concentration available at Guardian or Watsons for a few dollars. Remove the driftwood from the tank, spray or pour H2O2 directly over the affected areas, wait five minutes, then rinse thoroughly under tap water before returning it to the tank. Alternatively, spot-treat inside the tank using a syringe: apply 1–2 ml of 3% H2O2 directly onto the biofilm with flow turned off, wait five minutes, then resume filtration. Avoid exceeding 1.5 ml per 10 litres as a total tank dose to protect livestock.
When to Be Concerned
Standard white biofilm on new driftwood is harmless. Concern is warranted if the growth appears on established wood that has been submerged for months, if it has a distinctly foul smell, or if it appears alongside fish health issues. In these cases, the biofilm may indicate decaying wood rather than simple organic leaching. Soft, spongy wood sections should be cut away or the entire piece replaced. If fish show signs of stress — gasping, lethargy, or clamped fins — test water parameters immediately, as decomposing wood can spike ammonia in heavily stocked tanks.
Choosing Low-Biofilm Driftwood
Dense hardwoods produce less biofilm than softer, lighter species. Malaysian driftwood (often sold as “Malayan” in Singapore shops), iron wood, and mopani are among the cleanest options. Spider wood and cholla wood are popular for their dramatic shapes but notorious for heavy initial biofilm production. If visual appearance during the first month matters to you — for instance, in a client display or competition entry — opt for pre-soaked dense wood or use wood that has already been cycled in another tank. Many experienced Singapore aquascapers keep a “wood soaking bin” running constantly for future projects.
Timeline and Expectations
Most driftwood biofilm resolves on its own within three to six weeks. With active biological cleaners like amano shrimp, the visible period shortens to one to two weeks. Patience is the most important factor. Resist the urge to remove the wood entirely or dose chemicals aggressively — the biofilm is a natural, temporary phase. This guide on how to fix water mould driftwood aquarium issues should reassure you that the problem is cosmetic and self-limiting with proper management.
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