Silverfish

Primitive, wingless insects with silvery scales that live in humid, undisturbed places and feed on starch, paper and glue. They damage books and fabrics but are harmless to health.

Written by PestMan Editorial TeamTechnical review pendingPublished Updated
Size
10–15 mm
Eats
Paper, starch, glue, fabric
Health risk
None known
Main driver
Humidity and clutter
Risk level
Low

Silverfish identification

How to recognise silverfish

  • Carrot-shaped, 10–15 mm, covered in silvery-grey scales.
  • Three long bristles at the tail and long antennae.
  • Wiggling, fish-like movement.

Silverfish overview

Silverfish are among the oldest insect groups. They are common in Australian homes, particularly in humid climates and in roof voids, wardrobes, bookshelves and bathrooms.

They are a sign of humidity and undisturbed storage rather than poor cleanliness. Controlling moisture is central to managing silverfish.

Behaviour

  • Nocturnal and hide during the day.
  • Prefer high humidity; often fall into baths and sinks and cannot climb out.
  • Can live for years and survive long periods without food.

Habitat

  • Roof voids and insulation.
  • Wardrobes, bookshelves, storage boxes and linen cupboards.
  • Bathrooms and laundries.

Lifecycle

  • Egg → nymph → adult without metamorphosis; they keep moulting as adults.
  • Development is slow and depends on temperature and humidity.

Food sources

  • Starch and cellulose: paper, book bindings, wallpaper paste, cardboard.
  • Natural fabrics, dandruff, cereal and flour.

Entry points

  • Carried in on boxes, books and stored items.
  • Move from roof voids down through cornices and light fittings.

Infestation signs

  • Irregular holes or surface grazing on paper, photographs and fabrics.
  • Yellowish stains and tiny pepper-like droppings.
  • Silverfish in baths and sinks.

Health implications

  • Silverfish do not bite or spread disease.

Prevention

  • Reduce humidity with ventilation and dehumidifiers.
  • Store papers and fabrics in sealed plastic containers rather than cardboard.
  • Declutter storage areas and vacuum regularly.

Treatment overview

  • Reducing humidity and clutter is the foundation.
  • Roof-void treatments can reduce populations that drop into rooms; follow label directions.
Product safety

If you use any pest product, read the label first and follow it exactly — it is a legal requirement in Australia. Keep products away from children, pets and food areas as the label directs.

Questions about silverfish

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Sources & further reading

PestMan provides general information only and does not replace licensed pest-management, medical, veterinary or structural advice. Always read and follow product labels. Read our disclaimer.