How to Get Rid of Silverfish: The Complete UK Guide (2026)

Silverfish are one of the most common household insects in the United Kingdom, and yet they are among the least understood. If you have ever switched on the bathroom light at night and seen a small, silvery insect dart across the floor and vanish into a crack, you have almost certainly encountered a silverfish. While they are harmless to humans — they do not bite, sting, or carry disease — silverfish are a reliable indicator that your home has a humidity or damp problem, and in significant numbers they can cause real damage to books, documents, wallpaper, photographs, and clothing.

This guide provides a comprehensive, UK-focused overview of silverfish control. It covers what silverfish are, why they infest UK homes, where to find them, what damage they cause, the most effective DIY treatment methods, when to call a professional pest controller, and how to tell silverfish apart from other small household insects. Whether you are dealing with the occasional silverfish in the bathroom or a persistent infestation affecting multiple rooms, the information below will help you understand the problem and take effective action.

What Are Silverfish?

The common silverfish (Lepisma saccharina) is a small, wingless insect measuring 10 to 15 millimetres in length. It has a distinctive teardrop-shaped body covered in tiny, overlapping silver-grey scales that give it a metallic, fish-like appearance — hence the name. Silverfish have two long, thread-like antennae at the front and three tail bristles (cerci) at the rear, which together with their wriggling, fish-like movement make them unmistakable once you know what to look for.

Silverfish are among the oldest insects on Earth. Fossil records show that silverfish-like insects existed over 400 million years ago, making them older than the dinosaurs by a considerable margin. This extraordinary longevity is testament to how well adapted they are to their preferred environment: dark, warm, humid spaces with access to starchy or cellulose-based food sources.

Silverfish are strictly nocturnal. They avoid light and spend the daytime hidden in cracks, crevices, behind skirting boards, under baths, inside wall cavities, and in any other dark harbourage they can find. If you are seeing silverfish during the day, it is a strong indication that the population is significant — the available harbourage is becoming crowded, forcing some individuals out into the open. A single silverfish sighting at night is normal in many UK homes, but regular sightings or daytime sightings suggest a population that has grown beyond casual levels.

Individual silverfish can live for two to eight years — an exceptionally long lifespan for such a small insect. They are relatively slow breeders compared to many household pests. A female typically lays small clusters of eggs (usually fewer than 60 at a time) in cracks and crevices, and the eggs take two to eight weeks to hatch depending on temperature and humidity. However, because of their long lifespan and the fact that populations are rarely noticed until they become established, silverfish infestations tend to be persistent and can be difficult to eliminate without addressing the underlying environmental conditions that support them.

Silverfish are sometimes confused with firebrats (Thermobia domestica), a closely related species. Firebrats are similar in size and shape but have a mottled brown-grey appearance rather than the uniform silver of the common silverfish. Firebrats prefer significantly hotter environments — typically above 32°C — and are most commonly found near boilers, ovens, heating pipes, and commercial bakeries. In UK homes, the common silverfish is by far the more frequent species encountered.

What Causes Silverfish Infestations?

Understanding why silverfish infest UK homes is essential for effective control, because treating the cause is far more important than treating the symptom. Silverfish do not infest homes randomly — they are drawn to specific environmental conditions, and if those conditions exist in your home, silverfish will find them.

Humidity — The Number One Cause

Humidity is overwhelmingly the most important factor in silverfish infestations. Silverfish require relative humidity of 75 to 90 per cent to thrive. They cannot survive in dry environments for extended periods — their bodies lose moisture rapidly in dry air, and their eggs fail to develop below about 50 per cent relative humidity. This is why silverfish are most commonly found in bathrooms, kitchens, utility rooms, basements, and loft spaces — the rooms in a UK home where humidity is naturally highest. In many UK properties, particularly older ones with poor ventilation, these rooms regularly exceed 80 per cent relative humidity, creating perfect conditions for silverfish.

Damp and Condensation

Beyond routine humidity from showers and cooking, silverfish infestations frequently indicate a more serious damp problem. Rising damp, penetrating damp, leaking pipes (particularly slow leaks behind bath panels and under kitchen sinks), and chronic condensation all create the sustained high-moisture conditions that silverfish populations need to build. If you are finding silverfish in rooms that are not typically humid — such as bedrooms or living rooms — this is a strong early warning sign of a concealed damp problem that may need investigation by a damp surveyor.

Food Sources

Silverfish eat an extremely wide range of organic materials, all of which are abundant in the typical UK home. Their diet includes starch, cellulose, sugar, and protein. Specific food sources include: wallpaper paste (particularly in older homes with traditional paste), book bindings and paper, cardboard boxes, cotton and linen fabrics, photographs, flour, cereal, and other dried foods, dead skin cells (which accumulate in bedding and carpets), and even dead insects. The presence of abundant food sources alone will not cause a silverfish infestation — humidity must also be present — but a home with both high humidity and plentiful food provides ideal conditions for population growth.

Warmth

Silverfish prefer temperatures of 20 to 25°C, which is precisely the temperature range maintained in most UK homes. Central heating during autumn and winter creates warm conditions throughout the house, and combined with the condensation that often accompanies temperature differentials between warm rooms and cold external walls, the typical heated UK home inadvertently creates the warm, humid microclimate that silverfish prefer.

Clutter and Undisturbed Storage

Silverfish thrive in undisturbed areas with plenty of harbourage. Cardboard boxes stored in lofts, garages, cupboards, and under beds provide both food (the cardboard itself) and shelter. Stacks of newspapers, magazines, and books are particularly attractive. Old photograph albums, filing boxes of documents, and piles of fabric stored in rarely opened cupboards all provide excellent silverfish habitat. The less frequently an area is disturbed, the more hospitable it is for silverfish.

Building Age and Construction

Older UK properties are significantly more susceptible to silverfish infestations. Victorian and Edwardian terraced houses are particular hotspots due to their solid brick walls (which lack a cavity and are more prone to damp), original lime plaster (which absorbs and holds moisture), suspended timber floors with gaps and voids, and often inadequate ventilation by modern standards. Conversely, modern homes built to current Building Regulations, with cavity wall insulation, mechanical ventilation, and vapour barriers, tend to have lower baseline humidity and fewer silverfish problems — unless ventilation systems are not used properly.

For landlords, silverfish infestations in rented properties can be a sign of inadequate ventilation or unaddressed damp — issues that fall under the landlord's repair obligations. With the introduction of Awaab's Law, which imposes strict timescales on landlords to investigate and fix reported damp and mould hazards, silverfish infestations reported by tenants should be taken seriously as an early indicator of conditions that may also support mould growth. See our Landlord Pest Control guide for detailed information on responsibilities and legal requirements.

Where to Find Silverfish in Your Home

Silverfish are found throughout UK homes, but they concentrate in specific rooms and locations where humidity, warmth, and food sources converge. Understanding where to look is the first step to assessing the scale of your problem.

Bathrooms

Bathrooms are the single most common location for silverfish in UK homes. The combination of daily steam from showers and baths, warm temperatures, and the presence of damp towels, paper products, and dead skin cells makes bathrooms ideal habitat. Check behind the bath panel, under the bath itself, around the base of the toilet, inside vanity units, behind the cistern, in cracks between wall tiles and the bath surround, and around the extractor fan housing. The spaces behind and beneath bathroom furniture are often chronically damp and provide perfect harbourage.

Kitchens

Kitchens rank second after bathrooms. Steam from cooking, the dishwasher, and the washing machine (if located in the kitchen) generates humidity. Check under the kitchen sink (one of the most commonly infested spots), behind the dishwasher, behind the fridge (where warmth from the motor meets condensation), inside food cupboards (particularly those containing flour, cereal, and sugar), and in any gaps between units and walls.

Bedrooms

Finding silverfish in bedrooms is less common but not unusual, particularly in homes with widespread humidity problems. Silverfish are attracted to bedrooms with fitted wardrobes (especially those against external walls where condensation can form), bookcases, stacks of magazines beside the bed, and the dead skin cells that accumulate in mattresses and carpets. If you are seeing silverfish in bedrooms, this is typically a sign that humidity levels are elevated throughout the house, not just in wet rooms.

Loft Spaces

UK loft spaces are frequently humid due to poor ventilation, condensation on the underside of roof felt, and heat rising from the rooms below. Lofts are also the primary storage location for cardboard boxes, old books, photographs, and paperwork — all of which are food sources for silverfish. Check stored boxes carefully, particularly if the cardboard feels soft or shows signs of moisture damage. Improving loft ventilation with ridge vents and soffit vents can dramatically reduce humidity in this space.

Basements and Cellars

Basements and cellars in UK properties are prone to rising damp and condensation, creating some of the highest humidity levels in the home. Silverfish populations in basements can be substantial and may go unnoticed for years if the space is rarely visited. Check around pipe runs, skirting boards, stored boxes, and any areas where the walls feel damp to the touch.

Utility Rooms

Utility rooms housing washing machines and tumble dryers (especially condenser dryers or vented dryers that are not properly ducted outside) generate significant moisture. Combined with the typical presence of stored cleaning products, cardboard packaging, and rarely cleaned areas behind appliances, utility rooms are frequently overlooked but commonly harbour silverfish.

Silverfish Damage: What They Can Destroy

While silverfish are not dangerous to humans, they can cause meaningful damage to belongings, particularly items made from paper, fabric, and natural materials. The damage is often gradual and goes unnoticed until valuable items are examined closely.

Books and Documents

Silverfish feed on the glue in book bindings, the paper itself, and any starch-based coatings on glossy pages. Damage appears as irregular holes in pages, surface grazing that leaves thin, translucent patches, and damage to spines and covers where binding adhesive has been consumed. Over time, a silverfish-infested bookshelf can sustain significant damage, particularly to older books with traditional animal-based glues.

Wallpaper

Silverfish consume wallpaper paste, which can cause wallpaper to loosen and peel away from walls. They also graze on the surface of wallpaper, leaving irregular marks and small holes. This damage is most common behind furniture and in corners where silverfish activity goes unnoticed.

Clothing and Fabrics

Silverfish eat cotton, linen, silk, and starched or soiled synthetic fabrics. Damage typically appears as irregular holes with slightly yellowed edges. Clothing stored in damp conditions for extended periods is most at risk, particularly items in rarely opened drawers and wardrobes against external walls.

Photographs

Silverfish are attracted to the gelatin emulsion used in traditional photographic prints. They can consume the surface of photographs, leaving them permanently damaged with a characteristic surface grazing pattern. Old family photographs stored in damp lofts or basements are particularly vulnerable.

Stored Food

Silverfish will eat flour, cereal, oats, sugar, dried pasta, and other starchy dried foods if packaging is not sealed. While they do not consume large quantities, their presence in food cupboards is unpleasant and contaminating. Silverfish droppings — tiny black specks resembling ground pepper — are often the first sign of their presence in food storage areas.

DIY Silverfish Treatment Methods

Effective silverfish control follows a clear hierarchy: fix the environment first, then treat the insects. Any insecticidal treatment applied without first addressing the underlying humidity problem will provide only temporary relief — the silverfish will return as long as conditions remain favourable. Work through the following methods in order, starting with the most important.

Reduce Humidity (Most Important)

Because silverfish cannot survive in dry conditions, reducing indoor humidity is the single most effective — and most permanent — method of silverfish control. Target a relative humidity below 50 per cent throughout the home. Practical steps include:

• Use a dehumidifier. An electric dehumidifier with a 10–12 litre per day capacity is sufficient for most UK homes. Place it in the room with the worst silverfish problem and run it continuously until humidity drops below 50 per cent, then use a hygrometer to monitor and maintain levels. A dehumidifier with a built-in humidistat will cycle on and off automatically to maintain your target humidity.
• Install or upgrade extractor fans. Every bathroom and kitchen should have a mechanical extractor fan. For bathrooms, choose a fan with a humidistat that runs automatically when humidity rises above a set threshold and continues for a timed period after humidity drops — this ensures the fan runs long enough to clear moisture from showers. An extraction rate of at least 15 litres per second is recommended for bathrooms.
• Improve ventilation. Open windows for 15–20 minutes each day to allow air exchange, even in winter. Ensure trickle vents in double-glazed windows are open. Do not block air bricks in external walls. In loft spaces, ensure adequate ventilation through ridge vents and soffit vents.
• Do not dry clothes on radiators. Drying a single load of washing on radiators releases approximately 2 litres of water vapour into the air. Use a vented tumble dryer (ducted outside), a condenser dryer, or dry clothes outdoors whenever possible.
• Fix leaks promptly. Even small, slow leaks under sinks, behind baths, and from pipe joints create localised high-humidity zones that support silverfish. Check under sinks and behind appliances regularly.
• Consider a PIV unit. Positive Input Ventilation (PIV) systems, installed in the loft, push filtered, dehumidified air into the home, creating a slight positive pressure that displaces moist air. PIV units are highly effective at reducing condensation and humidity throughout a property and typically cost £300–£500 installed.

Remove Food Sources

While reducing humidity is the priority, removing accessible food sources makes your home less hospitable to silverfish and slows population growth. Store dried food (flour, cereal, sugar, pasta) in airtight containers rather than leaving them in open packets. Replace cardboard storage boxes with plastic boxes with clip-on lids. Vacuum regularly, including under furniture, along skirting boards, and in cupboard corners, to remove dead skin cells, crumbs, and debris. Remove piles of old newspapers, magazines, and paper clutter.

Seal Entry Points

Silverfish move through tiny gaps and cracks in the fabric of your home. While it is impossible to seal every potential entry point, addressing the most obvious ones can help reduce movement between rooms and from wall cavities into living spaces. Use silicone sealant to fill gaps around pipe penetrations (where pipes pass through walls and floors), cracks between skirting boards and walls, gaps around bath panels, and openings around electrical sockets and light fittings on external walls. Pay particular attention to bathrooms and kitchens where most silverfish activity occurs.

Trapping

Sticky traps (glue boards) are useful both as a monitoring tool and as a supplementary control method. Place sticky traps along skirting boards in bathrooms, kitchens, and other areas where silverfish have been seen. Check traps weekly — the number of silverfish caught gives a reliable indication of population levels and helps you assess whether your environmental improvements are working. For a DIY trap, place a glass jar wrapped in masking tape (for grip) with a small piece of bread or damp paper inside. Silverfish climb up the tape and fall into the jar but cannot climb the smooth glass interior to escape.

Insecticidal Treatments

Once humidity is under control and food sources are reduced, insecticidal treatments can help eliminate remaining silverfish and accelerate the decline of the population.

• Diatomaceous earth (food grade). This is the most effective and widely recommended DIY treatment for silverfish. Diatomaceous earth is a fine, chalk-like powder made from the fossilised remains of diatoms (microscopic aquatic organisms). It works mechanically rather than chemically — the microscopically sharp particles damage the silverfish's waxy outer coating, causing it to dehydrate and die. Sprinkle food-grade diatomaceous earth behind skirting boards, under baths, inside cupboard corners, along pipe runs, and in any dry crevices where silverfish harbour. It is safe for use in homes with children and pets (food-grade only), but note that it only works in dry conditions — if the powder gets damp, it loses its effectiveness.
• Permethrin-based sprays. Residual insecticidal sprays containing permethrin can be applied to cracks, crevices, and harbourage areas. Spray behind skirting boards, under baths, and along pipe runs. Follow the manufacturer's instructions carefully and ensure adequate ventilation during and after application.
• Boric acid powder. Boric acid is an effective insecticidal dust that kills silverfish through ingestion and contact. Apply it to cracks, crevices, and voids in the same way as diatomaceous earth. Keep boric acid away from areas accessible to children and pets, as it is toxic if ingested in quantity.

When to Call a Professional

Many silverfish problems can be resolved with DIY methods, particularly when the root cause is straightforward inadequate bathroom ventilation. However, there are situations where professional help is the more practical and effective option. A qualified pest controller can identify harbourage locations, apply professional-grade insecticidal treatments to areas that are difficult for homeowners to access, and advise on the environmental changes needed to prevent recurrence.

Consider calling a professional if: you are seeing silverfish during the day, which indicates a significant population. If silverfish are present in multiple rooms rather than being confined to the bathroom, this suggests a wider humidity problem and a larger infestation. If silverfish are damaging valuable items — books, documents, photographs, or clothing — professional treatment can bring the population under control more quickly than DIY methods alone. If you have been applying DIY treatments for four to six weeks without noticeable improvement, a professional assessment is warranted. If you suspect structural damp (rising damp, penetrating damp, or a concealed leak) is contributing to the problem, you may need both a pest controller and a damp surveyor. If you are a landlord receiving complaints from tenants about silverfish, professional treatment and a damp investigation demonstrate that you are taking the issue seriously and meeting your repair obligations.

Silverfish vs Other Small Insects

Silverfish are often confused with several other small insects commonly found in UK homes. Correct identification is important because the treatment approach differs significantly between species. Here is how to tell silverfish apart from the most commonly confused insects.

Silverfish vs Firebrats

Firebrats (Thermobia domestica) are the closest relative of the common silverfish and are very similar in size and shape. The key difference is colour: firebrats have a mottled brown-grey appearance rather than the uniform silver of Lepisma saccharina. Firebrats prefer significantly hotter environments, typically above 32°C, and are most commonly found near boilers, ovens, heating pipes, and in commercial bakeries or laundries. If you find a silverfish-like insect near a heat source, it is more likely to be a firebrat. Treatment methods are similar for both species.

Silverfish vs Booklice (Psocids)

Booklice (Psocoptera) are much smaller than silverfish, typically only 1 to 2 millimetres in length. They are pale, translucent, or light brown and are often mistaken for tiny lice. Like silverfish, booklice are a strong indicator of damp — they feed on microscopic mould that grows on surfaces in humid conditions. Finding booklice in your home means the same thing as finding silverfish: your humidity levels are too high. Reducing humidity to below 50 per cent relative humidity will eliminate both silverfish and booklice. Booklice are completely harmless.

Silverfish vs Woodlice

Woodlice are not insects but crustaceans (related to crabs and lobsters). They are grey, segmented, oval-shaped, and significantly larger than silverfish at 10 to 15 millimetres. They curl into a ball when disturbed (in the case of pill woodlice) and move slowly compared to the rapid darting movement of silverfish. Woodlice require very high moisture levels and are typically found in basements, cellars, and ground-floor rooms with serious damp problems. Like silverfish, their presence indicates excess moisture.

Silverfish vs Carpet Beetles

Carpet beetles (Anthrenus and Attagenus species) are small (2–4 mm), round or oval, and often have a mottled brown, black, and white pattern. Adult carpet beetles are relatively harmless, but their larvae — small, hairy, caterpillar-like creatures known as “woolly bears” — cause significant damage to carpets, clothing, and fabrics made from natural fibres (wool, silk, cotton). Unlike silverfish, carpet beetles are not linked to humidity — they are attracted to natural fibres and can infest even dry homes. If you are finding fabric damage but no silverfish, carpet beetles may be the culprit. See our dedicated carpet beetle control guide for full identification, treatment, and prevention advice.

Recommended Silverfish Treatment Products

Below are two of the most effective products for silverfish control in UK homes. For a comprehensive comparison of all the best silverfish treatments — including insecticidal powders, traps, sprays, and dehumidifiers — see our dedicated Best Silverfish Treatments UK 2026 review page.

Find a Pest Control Provider

PestPro Index lists verified, accredited pest control professionals in cities across the UK. If you need help with a silverfish problem — whether it's a professional spray treatment, a damp investigation, or advice on humidity control — use the links below to find pest control specialists in your area.

For a detailed breakdown of pest control costs across all common UK pests, including silverfish treatment and damp surveys, see our Pest Control Costs UK 2026 guide. If silverfish are not the only pest you are dealing with, you may also find our other guides helpful: how to get rid of rats, how to get rid of mice, how to get rid of cockroaches, how to get rid of fleas, how to get rid of ants, how to get rid of moths, how to get rid of foxes, how to get rid of squirrels, and pigeon control. Landlords dealing with silverfish issues in rental properties should consult our landlord pest control guide, and businesses may benefit from our commercial pest control guide. For product reviews, browse our best silverfish treatments, best rat traps, best mouse traps, best wasp killers, best cockroach killers, best flea treatments, best ant killers, best moth killers, best bed bug treatments, best fox deterrents, and best squirrel deterrents guides.

Frequently Asked Questions

Are silverfish harmful to humans?

No. Silverfish do not bite, sting, or carry disease, so they pose no direct health risk to humans. However, they are a nuisance pest and one of the strongest indicators of a damp or humidity problem in your home. They can cause damage to books, paper, photographs, wallpaper, clothing, and stored food items. If you are finding silverfish regularly, it is worth investigating the moisture levels in your home and taking steps to reduce humidity. See our section on DIY treatment methods for practical advice on reducing humidity and eliminating silverfish.

Why do I keep finding silverfish in my bathroom?

Bathrooms are the most common room for silverfish because of the high humidity generated by showers and baths. Inadequate ventilation is almost always the root cause. If your bathroom does not have an extractor fan, or if the fan is underpowered or does not run for long enough after use, moisture builds up and creates ideal conditions for silverfish. Installing a quality extractor fan with a humidistat that runs automatically when humidity rises is often all it takes to eliminate a silverfish problem entirely. The fan should run for at least 20 minutes after each shower or bath to fully clear the moisture.

Do silverfish mean my house is damp?

Yes. Silverfish are one of the strongest indicators of excess moisture in a home. They require relative humidity of 75 to 90 per cent to thrive and will not survive in dry environments. Finding silverfish consistently — particularly in rooms other than the bathroom — means your home's humidity levels need attention. This could indicate condensation damp, inadequate ventilation, rising damp, or leaking pipes. Addressing the moisture problem will not only eliminate silverfish but also prevent mould growth and protect your property from damp-related deterioration. For landlords, tenant reports of silverfish should be treated as an early warning of conditions that may also breach the Homes (Fitness for Human Habitation) Act 2018.

How do I get rid of silverfish permanently?

The key to permanent silverfish control is fixing the humidity problem first. Use a dehumidifier to bring indoor humidity below 50 per cent relative humidity, install extractor fans in bathrooms and kitchens, improve ventilation throughout the home, and fix any leaks or damp issues. Once humidity is under control, use diatomaceous earth in crevices and harbourage areas to kill remaining silverfish, and deploy sticky traps to monitor for activity. Without fixing the underlying moisture problem, any treatment — whether DIY or professional — will only provide temporary relief. See our best silverfish treatments review for detailed product recommendations.

Can silverfish damage clothes?

Yes. Silverfish eat cotton, linen, silk, and starched or soiled synthetic fabrics. Damage typically appears as irregular holes and yellow staining on affected garments. They are particularly attracted to items that have been stored in damp conditions for extended periods — clothing in rarely opened drawers, wardrobes against external walls, and garments stored in cardboard boxes in lofts and basements. To protect valuable clothing, store items in sealed plastic containers or vacuum-sealed bags rather than cardboard boxes, and ensure wardrobes and storage areas are well ventilated and dry. For more on insects that damage textiles, see our moth control guide.

Do silverfish come up through drains?

Silverfish do not live in drains and do not come up through the plumbing system. However, they are frequently found near drains because that is where bathroom and kitchen humidity is highest. Silverfish enter homes through tiny cracks and gaps in walls, floors, and around pipes. They are attracted to bathrooms and kitchens because of the moisture, not because they are emerging from the drainage system. If you are seeing silverfish near your bath or shower drain, focus on reducing humidity through improved ventilation rather than treating the drains themselves. Sealing gaps around pipe penetrations with silicone sealant can also help reduce silverfish movement into the room.