White biofilm on new wood and décor

It concentrates on fresh wood, cut ends or newly submerged organic décor. It may look cottony, slimy or translucent and regrow after removal until material nutrients decline. Shrimp and snails often graze it without illness; putrid odour, crumbling wood or irritated animals are not part of the usual benign pattern.

White biofilm on new wood is a soft, gelatinous or fluffy growth fuelled by soluble compounds released by the material. It includes bacterial communities and fungus-like organisms rather than one species. In most newly set-up tanks it is localised and self-limiting, but it must be distinguished from growth on living tissue or actual décor decay.

Sugars and other readily biodegradable compounds leach from wood and support pioneer colonisers. Temperature, available surface and low flow influence amount and duration. Its appearance neither proves biofilter maturity nor automatically means the wood is unsuitable; it describes a local colonisation process.

Escalate assessment if the mass appears on fish, amphibians, eggs or wounds, accompanies tissue erosion, or ammonia and nitrite rise. Foul odour, marked haze and obvious oxygen demand suggest wider decomposition. In those cases, simple wood biofilm is not an adequate explanation.

Saprolegnia and other oomycetes become clinically relevant when they grow on eggs or damaged tissue, not when confined to wood. Mineral deposits are hard or powdery; rotten wood loses structure and may smell foul. Peritrich colonies can look tufted but reveal stalked cells under microscopy.

Confirm that the mass originates on décor rather than an animal or eggs. Photograph the same area every few days, noting whether the material remains sound and the biofilm declines. A small portion viewed in water shows a soft matrix; microscopy can describe components but is rarely needed for a typical event.

Confirm that the mass originates on décor rather than an animal or eggs. Photograph the same area every few days, noting whether the material remains sound and the biofilm declines. A small portion viewed in water shows a soft matrix; microscopy can describe components but is rarely needed for a typical event.

If water and animals are normal, observation and good flow are sufficient. Visible growth can be siphoned during a change or brushed off outside the aquarium without disinfecting the entire décor. Remove the piece promptly if it smells abnormal, disintegrates or is not known to be aquarium-safe.

Medication or biocides are normally unnecessary. Light siphoning, pre-soaking wood and good water renewal manage appearance while the nutrient source is exhausted; some invertebrates graze it, but should not be purchased as a treatment. If it persists for many weeks, reassess the material and overall organic load.

Use wood and décor of known provenance, remove soft tissue or unstable bark and pre-soak where appropriate. Adding large amounts of new organic material gradually helps the system absorb leachates. Prevention aims to limit excess, not keep a natural surface sterile.

Escalate assessment if the mass appears on fish, amphibians, eggs or wounds, accompanies tissue erosion, or ammonia and nitrite rise. Foul odour, marked haze and obvious oxygen demand suggest wider decomposition. In those cases, simple wood biofilm is not an adequate explanation.