Silverfish in Sydney homes: where they hide and how to reduce them

What should you notice first?

• The room and exact spot where you see them—especially bathrooms, laundry areas, skirting boards and stored boxes.
• Whether activity is strongest in damp areas such as under sinks, near showers, around washing machines or in humid cupboards.
• Any paper, cardboard, books, magazines, fabrics or glue stored close to those places.
• Small yellow stains, holes in paper, or fine dust-like marks on shelves and along skirting boards.
• A clear photo if you are unsure what insect you are seeing.

Silverfish can be confused with other small household insects, and colour alone is not a reliable way to identify a species. If the activity is recurring, a photo, date and location give a technician much more to work with than a general description.

Reduce the moisture they rely on

Silverfish need humid conditions to thrive, so moisture control is usually the highest-value first step. Wipe down wet surfaces, dry the sink overnight and check beneath basins, washing machines and dishwashers for slow leaks or condensation. Use an exhaust fan during and after showers where one is fitted, and keep the bathroom door closed or ventilated so humidity does not settle into nearby rooms.

In very humid rooms, improving airflow and reducing clutter can help more than any chemical. Do not block required ventilation or drainage points as a pest-control shortcut.

Clear the hiding places they prefer

Silverfish shelter in narrow gaps, behind furniture, under skirting boards and inside boxes that are rarely moved. Vacuum along skirting boards, behind appliances and under beds, then dispose of the vacuum contents carefully. Reduce stacked cardboard, newspaper and paper bags, which hold moisture and provide food at the same time.

If you are in a rental or strata property, photograph recurring damp, leaks or building gaps and report them to the property manager or strata contact before making material changes. That record helps keep the maintenance issue clear.

Store vulnerable items and seal entry points

Books, documents, photo albums, craft supplies and fabrics can be kept in sealed containers or boxes, which also reduces dust and clutter. Check second-hand furniture, books and boxes before bringing them inside, since silverfish can travel in stored items. Close visible gaps around pipes, skirting boards and door thresholds where this does not affect drainage or ventilation.

Monitor over the next few weeks and know when to get help

Keep a simple note of sightings: date, room and approximate count. Recheck the damp spots, storage areas and gaps you have addressed. If you use a commercially labelled monitoring device or trap, use it only as directed and keep it inaccessible to children and pets. Activity that keeps returning after moisture, storage and entry-point work may point to a larger harbourage in a wall cavity, sub-floor or ceiling space.

• Activity continues after several weeks of moisture, cleaning and storage changes.
• You see silverfish in multiple rooms or around wall cavities, sub-floor spaces or roof voids.
• Books, documents, clothing or stored goods are being damaged in a way you cannot control.
• The same damp or building defect keeps recreating the conditions they need.
• You are unsure what insect you are seeing, or children, pets, allergies or food-preparation areas make treatment planning more sensitive.

A targeted inspection can identify likely harbourage and the appropriate next step. It is usually more useful than repeated spraying without knowing where the activity begins.