How to Get Rid of Silverfish in Your Home

The fastest way to learn how to get rid of silverfish is to stop treating it like a bug problem and start treating it like a moisture problem. These wingless, carrot-shaped insects need damp, humid air to survive, so the single most effective move is to dry out the rooms where they live, then back that up with cleanup, cracks-and-crevices dusts, and traps. Spraying insecticide around the baseboards without lowering the humidity almost always fails, because you are killing the visible bugs while leaving the conditions that keep producing them.

This guide walks through what silverfish are, why they showed up in your home, and a practical, step-by-step plan that works in a real house, not just a lab. It leans on university extension research and entomology sources, and it flags where the evidence is thinner so you can make your own call.

What Are Silverfish, and Why Are They in My House?

Silverfish (Lepisma saccharina, along with the related long-tailed silverfish Ctenolepisma longicaudata) are small, teardrop-shaped insects roughly 3 to 12 mm long, covered in shiny silver-gray scales, with two long antennae at the front and three bristle-like tail filaments at the back. They move with a quick, wriggling, fish-like motion, which is where the name comes from. Their close cousin, the firebrat (Thermobia domestica), looks similar but prefers hot spots like areas near furnaces, water heaters, ovens, and hot pipes.

They are ancient, primitive insects. Unlike most bugs, silverfish keep molting even after they reach adulthood, and they are slow to develop, taking anywhere from about three months to two years to mature depending on conditions, with lifespans that can reach a few years. That slow, persistent life cycle is part of why an untreated population feels like it never quite goes away.

What Causes Silverfish to Appear?

Two things draw silverfish into a home and keep them there: moisture and food. Of the two, moisture is the one that actually decides whether they can breed and build a population.

Silverfish are moisture-dependent insects. They thrive in humid air and struggle in dry conditions. Extension and entomology sources consistently point to high relative humidity as the driver of successful reproduction, with commonly cited figures putting the comfortable zone somewhere above roughly 70 to 75% relative humidity, and egg survival dropping sharply in drier air. The exact thresholds vary between sources and between species, so treat specific percentages as guidance rather than gospel, but the direction is not in dispute: dry air works against them, damp air works for them.

That is why silverfish are so strongly associated with basements, bathrooms, laundry rooms, kitchens, attics, crawl spaces, and the backs of cabinets against exterior walls. A plumbing leak under a sink, condensation on cold pipes, poor bathroom ventilation, or a damp basement can all create a pocket of humid air that is perfectly hospitable even when the rest of the house feels fine.

What Attracts Silverfish Once They’re Inside?

If moisture is the climate, food is the furniture. Silverfish eat materials high in starch, protein, and sugar, and they are notorious for going after carbohydrate- and cellulose-rich household items. According to university extension material, that menu includes:

• Paper and cardboard — books, magazines, stored documents, and especially the glossy, starch-coated paper in some magazines.
• Glue and adhesives — the paste behind wallpaper, book bindings, box seams, envelope and stamp glue, and the backing on some carpets and furniture.
• Natural fabrics — linen, cotton, silk, and rayon, particularly when stored in damp conditions or stained with food or sweat.
• Pantry starches — flour, cereal, oats, pasta, pet food, and other dry goods.
• Odds and ends — dead insects (including other silverfish and their own shed skins), dust, and dried residue.

This diet explains the classic signs of a silverfish infestation: irregular holes or notches chewed in paper and fabric, yellowish stains, tiny peppery droppings, and the shed scales they leave behind. Understanding what attracts silverfish is also the key to prevention, because every item on that list is something you can seal, store, or remove.

Why Do I Keep Seeing Silverfish in the Bathroom?

The bathroom is silverfish headquarters for a simple reason: it is the most reliably humid room in most homes. Hot showers, poor ventilation, condensation on tile and pipes, and the occasional slow leak create exactly the damp microclimate silverfish need. On top of that, bathrooms offer food in the form of cardboard product boxes, tissue and toilet paper, the glue in wallpaper, and the paper backing on drywall.

If you are finding silverfish in the bathroom — often stranded in the sink or tub, where they fell in and could not climb the slick surface back out — that is your clearest signal that humidity control needs to start there. Run the exhaust fan during and for 20 to 30 minutes after every shower, fix any dripping fixtures, caulk gaps around the tub and baseboards, and consider a small dehumidifier if the room stays muggy. Fixing the bathroom often does more to shrink the overall population than any spray.

Do Silverfish Bite, and Are They Dangerous?

Here is the reassuring part: silverfish do not bite humans, and they are not known to carry or transmit disease. Their mouthparts are built for scraping and rasping at starchy surfaces, not for piercing skin. They do not sting, they are not venomous, and they are not a threat to people or pets in the way that, say, bed bugs or fleas are.

The honest caveat is about allergies, not bites. Research has identified a silverfish protein (a tropomyosin designated Lep s 1) that can act as an allergen, and some sensitized people — particularly those with existing asthma or rhinitis — may react to silverfish particles and shed scales in household dust. This is a documented but relatively niche concern, and the evidence base is smaller than for dust mites. For the vast majority of households, silverfish are a nuisance and a property-damage problem, not a health hazard.

Make no mistake, though: the property damage is real. Left alone, a population can quietly ruin books, family photos, important documents, wallpaper, and stored clothing. “Harmless to you” is not the same as “harmless to your stuff.”

How to Get Rid of Silverfish: A Step-by-Step Plan

The reliable way to clear an infestation is to run moisture control, sanitation, direct treatment, and sealing at the same time. Doing only one of these is why so many DIY attempts stall. Here is the order that works.

1. Find the moisture first. Walk the house with a cheap hygrometer (humidity meter). Check basements, bathrooms, laundry areas, under sinks, around the water heater, and inside closets on exterior walls. Anywhere reading much above 50% relative humidity is a silverfish-friendly zone and a priority.
2. Dry those areas out. This is the heart of the whole project. Run a dehumidifier in damp basements and target the drier end of the range (many homeowners aim for somewhere around 45 to 50% relative humidity). Add or upgrade exhaust fans in bathrooms and the laundry room. Improve airflow in closets and crawl spaces. Fix plumbing leaks, insulate sweating cold-water pipes, and clear clogged gutters that push water against the foundation.
3. Remove the food and the harborage. Silverfish hide in the clutter that also feeds them. Clear out old cardboard boxes, newspaper and magazine stacks, and paper you no longer need. Move stored books and documents into sealed plastic bins instead of cardboard. Transfer pantry staples like flour, cereal, and pet food into airtight containers. Vacuum cracks, baseboards, and closet corners to pick up eggs, scales, and droppings, then empty the vacuum outside.
4. Treat the cracks and crevices with a drying dust. Silverfish travel and hide in gaps. A light dusting of diatomaceous earth or boric acid placed into cracks, along baseboards, behind appliances, under sinks, and in wall voids works by abrading or poisoning insects that walk through it. University extension sources list both as drying agents registered for this use. Apply a thin, barely visible layer — a thick pile does nothing because insects walk around it — and keep it in dry, hidden locations. (See the safety notes below before you reach for either one.)
5. Set traps to catch what’s left and to monitor. Place sticky insect traps along baseboards and in corners where you have seen activity. For a cheap homemade option, use the classic jar trap: wrap a small glass jar in masking tape so the outside is climbable, drop a bit of bread or a starchy lure inside, and set it out overnight. Silverfish climb in to feed and cannot scale the slick glass interior to escape. The rolled-newspaper trap works on the same idea — dampen a rolled-up newspaper, leave it out overnight so silverfish crawl inside to hide and feed, then seal it in a bag and throw it out (or burn it, where that is safe and legal) in the morning.
6. Seal them out. Caulk gaps around pipes, baseboards, window and door frames, and where walls meet floors. Repair torn window screens and add door sweeps. Sealing does double duty: it removes hiding spots and blocks new silverfish from migrating in from wall voids, attics, or neighboring units.
7. Wait, monitor, and repeat. Silverfish are slow breeders, so results come over weeks, not overnight. Check your traps and re-dust after cleaning or any moisture event. If humidity stays low and food stays sealed, the population declines and eventually collapses because the environment can no longer support reproduction.

How Do I Get Rid of Silverfish Naturally?

If you want to know how to get rid of silverfish naturally — with low-toxicity methods and minimal chemicals — the good news is that the most effective tactic of all, lowering humidity, is completely non-chemical. A dehumidifier, better ventilation, and leak repairs are the natural approach, and they are also the approach that actually ends the problem.

Beyond that, the genuinely useful low-toxicity tools are:

• Diatomaceous earth — a mineral powder (use the food-grade type for home use) that physically damages insects’ protective coating. It is mechanical, not a poison, but you should still avoid breathing the dust.
• Sticky traps and the jar/newspaper traps — zero chemicals, good for both catching and monitoring.
• Rigorous decluttering and airtight storage — removing food and damp hiding spots is “natural” in the truest sense.

Now the popular remedies that are weaker than the internet suggests. Cedar and bay leaves are frequently recommended as natural repellents. The realistic expectation is modest: these may have some repellent effect at close range, but they will not clear an established infestation on their own, and the evidence for them is largely anecdotal. The same goes for essential oils like lavender or citrus. Treat them as minor, optional supplements to moisture control, not as the main event. If a method does not address dampness, it is at best a bandage.

What Actually Works vs. Silverfish Myths

Because silverfish advice online is heavy on folk remedies, it helps to separate the load-bearing tactics from the decorative ones.

• Myth: “Spraying insecticide around the room will fix it.” Reality: surface sprays kill the silverfish they contact but leave eggs in cracks and do nothing about the humidity that keeps producing new ones. Without moisture control, you are mowing the lawn, not pulling the roots.
• Myth: “Cedar blocks and bay leaves will drive them out.” Reality: mild repellency at best; no match for an established population.
• Myth: “They bite and spread disease, so this is urgent for my health.” Reality: they do not bite and are not known to transmit disease. The urgency is about protecting your belongings, plus allergy sensitivity in a minority of people.
• Myth: “If I don’t see them, they’re gone.” Reality: silverfish are nocturnal and secretive. Traps are a better gauge of success than daytime sightings.
• Fact that works: dry air. Lower the humidity and you remove the one condition silverfish cannot live without.
• Fact that works: cracks-and-crevices dusts. Diatomaceous earth and boric acid placed where silverfish travel outperform broadcast spraying.
• Fact that works: sealed food and sealed gaps. No food and no entry points means no sustainable population.

Which Method Should I Use? A Comparison

Different tools do different jobs. Here is how the main options stack up, including low-toxicity versus chemical choices.

Are Diatomaceous Earth and Boric Acid Safe to Use?

Both are widely used by homeowners and are listed in extension guidance as low-toxicity drying agents for crack-and-crevice treatment, but “low-toxicity” is not “no precautions.”

Diatomaceous earth harms insects mechanically rather than chemically, which makes it attractive for a natural approach. Use the food-grade grade for household pest work, wear a dust mask when applying it, and keep it out of the air you breathe — the fine powder can irritate lungs. It only works while dry, so reapply after any cleaning or moisture.

Boric acid is more potent and correspondingly needs more care. Keep it strictly out of reach of children and pets, never apply it on or near food-contact surfaces, and confine it to hidden cracks, voids, and gaps. It is effective precisely because it is toxic to insects, so treat it with respect. Always read and follow the product label, which is the legally binding set of instructions for any pesticide.

How Do I Keep Silverfish From Coming Back?

Prevention is the same lever as control: keep the house dry, clean, and sealed. Once the population is down, a light ongoing routine keeps it from rebuilding.

• Keep indoor humidity on the low side, especially in basements and bathrooms; run dehumidifiers and exhaust fans as needed.
• Fix leaks promptly and insulate pipes that sweat with condensation.
• Store books, documents, and seasonal clothing in sealed plastic bins, not cardboard.
• Keep pantry starches — flour, cereal, grains, pet food — in airtight containers.
• Break down and recycle cardboard quickly instead of letting it pile up in damp spaces.
• Vacuum regularly along baseboards, closet corners, and under furniture to remove eggs and food debris.
• Caulk and seal cracks, gaps around pipes, and spaces under baseboards; add door sweeps and repair screens.
• Keep a few sticky traps in known problem spots as an early-warning system.
• Declutter storage areas so there are fewer dark, undisturbed places to hide.

When Should I Call a Professional?

Most silverfish problems are genuinely DIY-friendly, because the core fix is environmental. But there are situations where a licensed pest-control professional earns their fee:

• The population won’t drop despite weeks of real moisture control, cleanup, dusting, and sealing.
• You can’t find or fix the moisture source — a hidden leak, a chronically damp crawl space, or a structural humidity issue that needs a contractor’s eye.
• The infestation is large or spread across many rooms, suggesting an established population in wall voids or the attic.
• You’re in a multi-unit building, where silverfish may be migrating from neighboring units and coordinated treatment is needed.
• Valuable materials are at risk — a book collection, archives, important documents, or heirloom textiles you can’t afford to lose.
• Someone in the home has a diagnosed insect allergy or asthma that may be aggravated by insect debris in dust.

A good professional will do more than spray. Expect them to inspect for moisture, identify the species (which can affect strategy), apply targeted crack-and-crevice treatments, and advise on the humidity and sealing fixes that make the result stick. If someone proposes blanket spraying with no mention of moisture, that is a sign to get a second opinion.

The Bottom Line

Knowing how to get rid of silverfish comes down to reframing the whole thing: this is a moisture-control project with a pest-control finish, not the other way around. Dry out the damp rooms, pull the paper and cardboard and loose food that feed them, dust the cracks with diatomaceous earth or boric acid, set a few traps to monitor your progress, and seal the gaps that let them travel and hide. Skip the dramatic sprays and the folk cures that leave the dampness untouched. Silverfish can’t bite you and won’t make you sick, but they will chew through your books, clothes, and keepsakes if you let them — and the surest way to stop them is to make your home a place where they simply can’t thrive.