What we deal with
Three types turn up in the Western Cape. The common silverfish, Lepisma saccharina, is shiny silver-grey, carrot-shaped and moves like a fish wriggling; it prefers cool, damp places like bathrooms and laundries. The grey silverfish, Ctenolepisma longicaudata, is larger and greyer with long tail filaments, and is very common in Cape Town homes, roof spaces and bookshelves because it tolerates drier conditions. The firebrat, Thermobia domestica, is mottled brown and lives in hot spots around geysers, ovens and boiler rooms. All of them are slow-breeding but long-lived, so a small population can build up quietly over years.
Signs to look for
Tick every sign you have noticed. It takes ten seconds.
Why it matters: Fishmoths do not bite or spread disease, but they cause slow, steady damage. They eat the glue in book bindings and wallpaper, the starch in fabrics and paper, and the surface of photographs and documents. For offices, schools, libraries and archives, they can damage records that cannot be replaced. Their presence is also a strong clue to damp or poor ventilation that may be causing other problems in the building.
How we treat it
Fishmoths often live in roof spaces, wall voids and behind cornices, so a fine insecticidal dust blown into the ceiling void is one of our most effective tools. Inside, we apply a targeted residual treatment into cracks, cupboard corners, skirting gaps and behind bookshelves rather than spraying open surfaces. Fishmoths are long-lived and lay eggs in hidden cracks, so treatments that keep working for a while are more useful than a quick knockdown. We pair the treatment with advice on damp, ventilation and storage, because changing the conditions is what stops them coming back.
- Confirm and identify
We confirm it is fishmoths and not booklice or another small insect, which need different handling.
- Find where they live
The technician checks the roof space, cupboards, bookshelves, bathrooms and stored boxes for the main population.
- Check for damp
We look for leaks, poor ventilation and damp walls, because fishmoths follow moisture.
- Treat voids and cracks
Dust goes into the roof space and voids, and residual products into cracks, skirtings and cupboard corners.
- Report and remedial advice
You get a post-treatment report covering what we treated and what to change in storage and ventilation.
Things most people don't know
Many people think fishmoths only eat paper. They also go after the glue in wallpaper and book bindings, starch in fabrics, and even dried food crumbs and dead insects in cupboards.
When a technician deals with fishmoths, the first place they look is up. The roof space is often where the main population lives, out of sight, especially with the grey silverfish common in Cape Town.
A frequent mistake is spraying the cupboard and leaving everything else as it was. If the cardboard boxes and damp corners stay, the fishmoths will be back within a few months.
When it peaks in Cape Town
Fishmoths are active all year because they live indoors, but Cape Town's damp winters make them more noticeable as moisture rises in roofs, walls and cupboards. Grey silverfish in the roof space may become more visible in summer when the ceiling heats up and pushes them down into the rooms below.
DIY or call a professional?
Moving books into sealed boxes and running a dehumidifier will help more than any spray from the shop. DIY sprays rarely reach the roof space or wall voids where the main population lives. If you are seeing them in several rooms or dropping from the ceiling, get the roof space treated professionally.
What affects the price
The price depends on the size of the property, how many rooms and cupboards are affected, and whether the roof space needs to be treated. Easy access to the ceiling void keeps the job simpler, while a home with lots of built-in cupboards and shelves takes more time. Offices, archives and storerooms with large amounts of paper are quoted separately, and every quote is free.
Preventing it coming back
- Store books, documents and photographs in sealed plastic boxes, not cardboard, especially in garages and storerooms.
- Improve ventilation in bathrooms and laundries with an extractor fan or by keeping a window open after showers.
- Fix leaks under basins, around geysers and in the roof, since fishmoths need moisture.
- Vacuum regularly inside cupboards, along skirting boards and behind furniture to remove eggs and food sources.
- Avoid stacking old newspapers, magazines and cardboard boxes in cupboards for long periods.
- Seal cracks around skirting boards, cornices and built-in cupboards where they hide and lay eggs.
Frequently asked questions
Are fishmoths and silverfish the same thing?
Yes. Fishmoth is the common South African name for silverfish, and it covers a few related species, including the grey silverfish common in Cape Town.
Do fishmoths bite?
No, they do not bite people or pets and do not carry disease. The problem is the damage they do to paper, books, photographs and fabrics.
Why are fishmoths falling from my ceiling?
That usually means there is a population in the roof space. Treating the ceiling void with a dust is the most effective way to deal with it.
Do fishmoths mean I have damp?
Often, yes. Common silverfish in particular need high humidity, so seeing them regularly in one room is a good reason to check for leaks or poor ventilation.
How long does a fishmoth treatment last?
Our treatments carry a minimum 3-month guarantee. Fixing damp and changing storage habits makes the result last much longer.
Can fishmoths damage clothes?
They can graze cotton, linen, silk and starched fabrics, particularly items stored for long periods in damp cupboards. They are less of a problem on synthetics.
Fishmoth Control by area
We cover all of these suburbs from our base in Brackenfell. Pick yours for local advice.
