Crawling insect · Lepisma saccharina · Last updated 14 August 2026
Silverfish
The silverfish (Lepisma saccharina) is a primitive wingless insect that proliferates in damp, dark environments. It feeds on starch- and cellulose-rich materials — paper, glue, textiles, food residues.
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Nocturnal and fast, the silverfish goes unnoticed for months. It's not dangerous to health but can damage books, wallpaper, clothing and stored foodstuffs. A large presence signals a moisture problem. Treatment combines a residual insecticide in transit areas with correcting the ambient humidity.
Identify
Signs of infestation
- A flattened silver insect, 10 to 15 mm, darting quickly into a crack when the light comes on
- Irregular gnaw marks on wallpaper, book spines, cardboard packaging and cotton fibres
- Small black dot-shaped droppings (like grains of pepper) on shelves or in drawers
- Transparent shed skins (exuviae) in cracks and corners
Where it's found
Thigmotactic (it likes contact with surfaces), the silverfish (Lepisma saccharina) lives in bathroom tile cracks, behind radiators, in cardboard archive boxes and under sinks. It thrives above 70% humidity and 20°C. An individual can live 3 to 5 years.
Impact
Associated risks
Damage to documents and paper
Feeds on cellulose, starch and glue: wallpaper, archives, old book bindings, labels and packaging. Damage is often discovered late, as the insect is nocturnal.
Moisture indicator
Like the woodlouse, its lasting presence signals high relative humidity (>70%). Chronic condensation in poorly ventilated bathrooms and kitchens is the usual cause in Belgium.
Good practice
Prevention
- 01Actively ventilate the bathroom and kitchen after every use. Mechanical ventilation (MVHR) is the lasting solution to keep humidity under 60%
- 02Store paper archives in closed plastic boxes, not open cardboard boxes in the cellar
- 03Seal tile cracks with silicone joint and repair faulty bath seals
Frequently asked questions
What you're asking
Are silverfish dangerous?
No, silverfish don't sting, don't bite and don't transmit diseases. They can nevertheless cause material damage: they gnaw wallpaper, books, natural textiles and dry foods (flour, cereals). A dense infestation generally indicates excess humidity that needs correcting.
Why do we get silverfish in the bathroom?
The bathroom combines the silverfish's ideal conditions: high humidity, stable temperature, dark areas under furniture. It often enters via pipework or cracks in the joints. Improving ventilation and fixing leaks reduces the pressure before treatment.
How do I eliminate silverfish for good?
A residual insecticide treatment in transit areas (skirting boards, joints, under sinks) works within days. To prevent reinfestation, the moisture source must be treated: stronger ventilation, a dehumidifier, sealing joints. Without moisture correction, the problem returns.
Insect Control
Related pests
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