Best Silverfish Treatments UK 2026 — Sprays, Traps, Powder & Dehumidifiers

Four products, and only two of them are insecticides. The other two are a glue trap that tells you where the insects are and a dehumidifier that removes the thing they need. That split is the argument of this page.

The Damp Is the Infestation

The University of California’s Statewide IPM Program puts the condition ahead of the insect: “Silverfish require a lot of moisture, so using dehumidifiers in closed spaces can help discourage these pests.” (UC IPM). That is why a dehumidifier sits on a page of treatments and is not an odd inclusion.

Before any of it, the same source says to find out where they actually are: “To detect and monitor infestations, use cockroach sticky traps.” A trap is not a lesser purchase than a spray; it is the step that tells you where the spray should go.

What the Label Governs

The spray and the powder are insecticides and each carries a label setting out where it may be applied, at what rate, and what has to be kept away from it. The powder’s own listing title describes it as HSE approved and tested. That is the maker’s description of its product, and what any such approval covers is set out in the approval itself and on the label, not here.

The glue trap carries no insecticide, and the dehumidifier is an appliance rather than a pesticide. Their instructions are still worth reading, but they are not governed by a pesticide label.

Where a Treatment Does Not Work

While the moisture is still there. UC IPM: “Insecticides won’t be effective unless you also remove the moisture, food, and hiding places that allow these pests to thrive.” (UC IPM). A treated skirting in a room that is still wet is a treated skirting in a room that is still wet.

At scale, at all, without the damp fixed. The same source is blunter about a large population: “It is almost impossible to control large populations of silverfish and firebrats unless you have removed dripping water and moist surfaces.”

As a bait. “However, baits aren’t very successful in treating silverfish and firebrats, because they tend not to feed on them.” There is no bait on this page for that reason, and the trap here catches by glue rather than by attracting with a poison.

Where the insects are not. UC IPM notes that these insects travel long distances while looking for food, so it can be difficult to pinpoint the source of an infestation. A treated area they never cross has done nothing.

What Decides the Choice

1. Whether you know where they are yet

UC IPM’s first instruction is monitoring, not treatment. If you have seen two silverfish in six months, the traps are the honest first purchase and the spray is premature.

2. Whether the room can be dried

A bathroom that ventilates properly and a cellar that does not are different problems. The dehumidifier is the only item here that acts on the condition rather than on the insect, and it is also the only one that will still be doing something in a year.

3. Where the treatment has to go

The spray is listed for surfaces — walls, floors, carpets, furnishings. The powder is listed in a puffer pack for cracks, wall voids and the area around power points. A liquid and a dust are not competing products; they reach different places.

4. Whether the listing names an active

Both insecticides here do: cypermethrin on the spray at 0.1% w/w, and permethrin on the powder. The trap and the dehumidifier name none, because neither contains one.

If a Product Is Not the Answer

Ventilation. UC IPM notes that ventilation from fans can reduce relative humidity to a point that is intolerable to silverfish. An extractor fan that actually runs is a treatment.

Cleaning and repair. Its prevention list is keeping basements, laundry rooms and bathrooms clean and dry, patching holes and spaces around pipes and conduits, and repairing leaks and drips in plumbing. None of that is sold here.

Moving the books. It notes that collections of magazines, papers and books provide both food and harbourage, and suggests moving them around in the bookcase occasionally.

A damp problem rather than an insect one. Our commercial dehumidifiers page covers the larger machines, and our silverfish guide covers the house rather than the product.

Using Them

1. Trap before you treat. Corners and edges where foraging is likely, per UC IPM, and a week of watching before anything else is bought.
2. Fix the water. A drip under a sink outlasts every insecticide on this page.
3. Match the form to the place. Spray for surfaces, dust for voids and crevices; each listing states which it is for.
4. Keep dust dry. UC IPM notes that if dust deposits get wet and then dry they cake, and that moist areas may need re-treating.
5. Give it two to three weeks. UC IPM says a properly applied insecticide shows results in a few weeks, and that no result by then points at untreated areas rather than at the product.

The Four Compared

Every column below is what the Amazon listing itself states, with each claim attributed to the maker who makes it. Where a listing does not state something, the cell says so rather than guessing.

Frequently Asked Questions