How to Get Rid of Silverfish A Complete Ireland Guide
To get rid of silverfish, reduce the humidity that sustains them (ventilate, dehumidify, fix leaks), remove their food (store paper and dried goods in sealed containers, declutter), and treat them directly with traps, diatomaceous earth or a residual insecticide. Because silverfish are a damp problem, controlling moisture is the key to a lasting result - especially in Ireland's humid climate.
Silverfish are one of the most common and most persistent household insects in Ireland. If you keep finding those small, silvery, fish-shaped insects darting across the bathroom floor or lurking in the bath, this complete guide will help you get rid of them for good. We will cover what silverfish are, what causes them, a full step-by-step method to eliminate them, how to stop them coming back, and when it is worth calling a professional. It is written specifically for Irish homes, because our damp climate makes silverfish behave differently here than the generic overseas advice assumes.
What Are Silverfish?
Silverfish (Lepisma saccharina) are small, wingless insects about 12-19mm long, with a silvery-grey, teardrop or 'fish' shaped body, two long antennae at the front and three bristle-like tails at the back. They move with a distinctive wriggling, fish-like motion. They are nocturnal, fast-moving and shy away from light which is why you usually spot them when you switch on a light at night. They are harmless to people: they do not bite, sting or carry disease. Their downside is damage to belongings and the fact that they signal a damp problem.
What Causes Silverfish? (And Why Irish Homes Get Them)
Silverfish are caused by damp and high humidity, combined with a starchy food source. They need relative humidity above about 75% to thrive, and they feed on carbohydrates - paper, cardboard, wallpaper paste, book bindings, dried food and natural fabrics. Ireland's mild, damp climate and older, often under-ventilated housing stock keep indoor humidity high and provide condensation and cold-wall damp, which is why silverfish are so common here. For the full detail, see our guides on what causes silverfish and why you get silverfish in Irish homes.
The Golden Rule
- The golden rule: silverfish are a symptom of damp. You can kill the ones you see, but unless you reduce the humidity, more will breed. Every method below works better when combined with moisture control.
How to Get Rid of Silverfish: Step by Step
Step 1: Reduce the Humidity (the most important step)
This is where lasting silverfish control begins. In Ireland's damp climate it is also the step most often under-done:
- Ventilate - open windows after showering and cooking; use extractor fans in the bathroom and kitchen and let them run on after use
- Dehumidify - run a dehumidifier in persistently damp rooms; aim to keep relative humidity below about 50%, which silverfish cannot tolerate
- Fix leaks - repair dripping taps, leaking pipes and any source of damp; dry out under sinks and behind appliances
- Tackle condensation - improve heating and ventilation in cold, north-facing rooms where condensation forms on walls and windows
Step 2: Remove Their Food and Shelter
- Store paper, books, cardboard and documents in sealed plastic boxes rather than leaving them in humid rooms
- Keep dried foods - flour, cereal, oats, pet food - in airtight containers
- Declutter - silverfish shelter and breed in piles of paper, cardboard and books, especially in damp cupboards and attics
- Vacuum regularly, including cracks and crevices, to remove silverfish, eggs and food debris
Step 3: Treat the Silverfish Directly
With humidity and food addressed, treat the insects themselves. Options, from gentlest to strongest:
| Method | How It Works | Notes |
|---|---|---|
| Sticky traps | Small silverfish traps placed along skirting and in corners catch insects and show you where activity is worst. | Good for monitoring and light infestations. Non-toxic. |
| Diatomaceous earth | A fine natural powder that damages the insects' waxy coating, dehydrating them. Puff into cracks and crevices. | Keep dry to stay effective. Use food-grade; avoid inhaling the dust. |
| Jar trap (DIY) | A glass jar wrapped in tape with a little bread inside - silverfish climb in but can't climb out. | A cheap home-made monitor and trap. |
| Residual insecticide spray | A crawling-insect spray applied to harbourages, cracks and runs kills silverfish on contact and leaves residue. | Follow label instructions; keep away from food areas, children and pets. |
| Professional treatment | A PMU-licensed technician applies professional residual products and addresses the damp source. | Best for heavy or persistent infestations. See below. |
Step 4: Seal Them Out
Finally, close off the cracks and gaps silverfish use to travel and hide: fill gaps in skirting boards, around pipes, and in tiling and grout; seal gaps around window and door frames; and repair damaged plaster. This removes their hiding places and slows any re-population.
How Long Does It Take to Get Rid of Silverfish?
Be patient. Silverfish are slow-breeding but hardy, and an established population takes time to clear. With consistent humidity control, food removal and treatment, you should see a marked reduction within a few weeks, but fully clearing a well-established infestation can take one to two months. The single biggest factor in how long it takes and whether it lasts is how well you control the underlying damp. Rush the moisture step and the silverfish will simply return.
Natural vs Chemical Methods
Many people prefer to start with natural methods, and for a light silverfish problem they can work well:
- Natural options - dehumidifying, diatomaceous earth, cedar, dried bay leaves and cloves are traditional deterrents; sticky and jar traps are non-toxic
- Chemical options - residual crawling-insect sprays and insecticidal dusts are more powerful for heavier infestations
For most Irish homes, the most effective and lasting approach is a combination: control the humidity (natural), remove food and clutter (natural), and treat directly with the gentlest method that works for the level of infestation, stepping up to a residual insecticide or a professional only if needed.
When to Call a Professional
DIY works for many silverfish problems, but call a professional if:
- 1You are seeing silverfish regularly across several rooms, not just the occasional one
- 2You have controlled humidity and tried treatments for several weeks without lasting success
- 3Silverfish are damaging books, documents, wallpaper or stored clothing
- 4The problem is in a business - a hotel, guesthouse, archive, office or food premises
- 5You want the problem dealt with quickly and thoroughly, including expert assessment of the damp source
Professional Silverfish Treatment Across Ireland
When DIY isn't enough, Central Pest Control clears silverfish and helps you tackle the damp conditions Irish homes provide. PMU-licensed, fully insured, 35+ years' experience. See our silverfish treatment and control page, or call us for advice.
Frequently Asked Questions
How do I get rid of silverfish permanently?
The only way to get rid of silverfish permanently is to remove the damp and humidity they depend on. Ventilate and dehumidify, fix leaks and condensation, store paper and dried food in sealed containers, declutter, and treat the insects with traps, diatomaceous earth or a residual insecticide. Controlling the moisture is what makes the result permanent - treatment alone will not last if the damp remains.
What kills silverfish instantly?
A direct spray with a crawling-insect insecticide, or contact with diatomaceous earth, will kill silverfish. However, killing the ones you see does not solve the problem - the population will rebuild unless you reduce the humidity and remove their food. Focus on the underlying damp as well as the quick kill.
Do silverfish mean my house is damp?
Almost always, yes. Silverfish need high humidity to survive, so their presence is a reliable sign that part of your home is more humid than it should be - often a bathroom, kitchen, utility room or a spot with a leak or condensation. Addressing that damp is both the key to getting rid of silverfish and good for the building itself.
Are silverfish harmful to humans?
No. Silverfish do not bite, sting or carry disease and are harmless to people and pets. They damage belongings books, documents, wallpaper, photographs and stored clothing and they indicate a damp problem, but they pose no direct health risk.
Why do I suddenly have silverfish?
A sudden increase in silverfish, especially in autumn, usually means indoor humidity has risen often as damp weather sets in and homes are closed up and heated, driving condensation. An existing population becomes more active and visible. It can also follow a new leak or damp issue. Check for and address the moisture source.
Need Silverfish Help in Ireland?
Central Pest Control provides professional silverfish treatment across Dublin and Ireland. PMU-licensed, fully insured, FSAI/HACCP compliant, and family-run for 35+ years.
