Finding a small silver insect darting across the bathroom floor at night, or discovering ragged holes in a book you haven’t opened in months, usually means silverfish have settled in. They’re among the most common household pests in Australia, and while they’re harmless to people, they quietly damage books, photos, clothing, and wallpaper for years if left alone.
This guide covers what silverfish are, where they come from, the DIY steps that genuinely work, and when professional silverfish pest control is the better path. Allstate Pest Control has managed household pests across Adelaide and South Australia since 1986, and silverfish are a regular find during our inspections, especially in older homes.
What Are Silverfish?
Silverfish are wingless, teardrop-shaped insects, usually 12 to 19 millimetres long, covered in silvery-grey scales with three long bristles at the tail. They move with a distinctive wriggling, fish-like motion, which is where the name comes from. Silverfish are nocturnal and avoid light, so most people only ever see them at night or when moving stored boxes and furniture.
They’re also one of the oldest insects on earth, predating the dinosaurs, and that long history shows in how hardy they are. A silverfish can live for two to three years and survive for months without food, which is a big part of why casual DIY efforts so often fall short.
Where Do Silverfish Come From?
Silverfish come from two places: outside your home, and inside things you bring into it. Outdoors, they live under bark, in leaf litter, and in soil, entering houses through gaps around doors, windows, vents, and foundations. Indoors, they hitch rides in cardboard boxes, secondhand books, stored papers, and furniture, which is why infestations often start after a house move or after boxes come down from the roof void.
Once inside, silverfish head for humidity. Adelaide is a dry city, but every home has humid microclimates: bathrooms, laundries, under sinks, subfloors, cellars, and wardrobes against cold south-facing walls. Older stone homes across Adelaide’s established suburbs are particularly good silverfish habitat, with cellars, original timber floors, and decades of accumulated gaps. Seeing silverfish regularly is often the first hint of a moisture issue worth fixing for its own sake.
Signs of a Silverfish Problem
Silverfish are easy to miss until numbers build. Watch for:
- Live sightings at night, most often in bathrooms, laundries, and kitchens
- Irregular holes and grazed patches on paper, book bindings, cardboard, and wallpaper, where they’ve fed on the starch and glue
- Yellow stains on fabric or paper, left behind as they feed
- Tiny black droppings that look like ground pepper, in drawers, on shelves, and along skirting boards
- Shed skins, since silverfish moult throughout their lives and leave delicate translucent casings behind
Because one female lays up to a hundred eggs in cracks and crevices, a few sightings usually mean a larger population out of view.
What Do Silverfish Damage?
Silverfish feed on carbohydrates, particularly starches and cellulose. In practice, that means books, photographs, important documents, wallpaper, cardboard storage, and pantry goods like flour, oats, and cereals. In wardrobes, they go for cotton, linen, silk, and viscose, along with any garment carrying starch, sweat residue, or food marks. They won’t bite you or spread disease, but a long-running infestation ruins irreplaceable items, and their presence flags the damp conditions that also invite mould.