How to Get Rid of Silverfish: Dry Them Out and Keep Them Gone

Quick answer: To get rid of silverfish, take away the damp air they need: run a dehumidifier or exhaust fan until indoor humidity stays below 50%, fix leaks and move paper, cardboard and books out of basements and bathrooms. Then catch the ones you have with sticky traps along baseboards, dust cracks lightly with food-grade diatomaceous earth and seal gaps. Expect two to six weeks to see them fade out.

If you know how to get rid of silverfish, you know it’s less about killing bugs and more about changing the room. These fast, carrot-shaped insects live where it’s humid, dark and quiet, and they leave as soon as those rooms dry out.

The good news: silverfish don’t bite, don’t spread disease and don’t damage your house’s structure. The bad news: they chew book bindings, wallpaper paste, photos and some fabrics, and seeing one usually means there are more. Here’s the step-by-step plan, the few products that actually help and what to skip.

What are silverfish, and why are they in my house?

Silverfish are small (about half an inch to an inch long), wingless insects with silvery scales, two long antennae and three tail bristles. They wiggle when they run, which is where the “fish” name comes from. A close cousin, the firebrat, looks similar but is darker and prefers hot spots near furnaces, water heaters and dryers.

According to university extension entomologists, silverfish thrive at a relative humidity of roughly 75% to 95% and struggle to survive and breed in dry air. That’s why you find them in:

• Bathrooms, especially under sinks, behind toilets and around tubs.
• Basements, crawl spaces and laundry rooms.
• Attics with roof leaks or poor ventilation.
• Closets, bookshelves and storage boxes against cold exterior walls.
• Kitchens, where they find flour, cereal, pasta and crumbs.

They eat starches and sugars: paper, cardboard, book glue, wallpaper paste, cotton, linen, rayon, dandruff, dead insects and dry food. They’re nocturnal and can live for months with little food, and they live for several years, so a small population can hang around for a long time if the humidity stays high.

Signs you have silverfish (not something else)

• Small, irregular holes or scraped-looking surfaces on paper, book covers, photos or wallpaper.
• Yellowish stains or tiny pepper-like droppings on shelves and in boxes.
• Shed skins: silverfish molt many times during their lives.
• Quick, silvery insects that dart away when you turn on a light in a bathroom or basement.

If you’re finding holes in wool sweaters or rugs instead of paper, the culprit is more likely carpet beetle larvae. Our guide on how to get rid of carpet beetles helps you tell them apart. Fast brown insects in the kitchen at night could also be roaches, covered in how to get rid of cockroaches.

How to get rid of silverfish: step by step

1. Measure the humidity first. Put an inexpensive digital hygrometer in the room where you see them. If it reads above 60%, humidity is the root cause, and traps alone won’t fix it. The EPA recommends keeping indoor humidity between 30% and 50%.
2. Dry out the room. Run the bathroom exhaust fan during showers and for 20 minutes after. In basements and laundry rooms, run a compressor dehumidifier set to 45% to 50%. For a closet or small bathroom, a small unit can help, but see the honest note on mini dehumidifiers below. Our guide on how to reduce humidity in your house covers every room.
3. Fix leaks and wet spots. Check under sinks, around toilets and tubs, behind the washer and at the water heater. Repair dripping pipes, re-caulk tubs and showers and make sure gutters and downspouts send water away from the foundation.
4. Remove their food and hiding places. Move books, papers, photos, mail and cardboard boxes out of basements, bathrooms and garages. Store keepsakes in sealed plastic bins with tight lids. Put flour, cereal, pasta and pet food in airtight containers.
5. Declutter and vacuum. Vacuum baseboards, closet floors, shelves and cracks with a crevice tool to pick up insects, eggs, scales and crumbs. Empty the canister or bag outside. Clear piles of clothes and stacks of magazines they can hide under.
6. Set traps where you see them. Place sticky traps flat against the wall along baseboards, under sinks, behind the toilet and in closet corners. Check them every few days. More catches in one spot tells you where they hide.
7. Treat cracks lightly. Puff a very thin layer of food-grade diatomaceous earth into cracks, behind baseboards and under appliances, or use bait packets in places kids and pets can’t reach. Then seal cracks around baseboards, pipes and window frames with caulk.

Two DIY traps that work

The jar trap: wrap the outside of a small glass jar with masking tape so silverfish can climb up, put a piece of bread or a few cereal flakes inside, and set it where you’ve seen them overnight. They climb in but can’t get back up the slick glass. Empty it outdoors in the morning.

The newspaper roll: roll up a newspaper, dampen it slightly, secure it with rubber bands and leave it overnight. Silverfish crawl inside to hide. In the morning, seal the roll in a bag and throw it out. These tricks are great for gauging how many you have, but they won’t clear a population by themselves.

How to use diatomaceous earth safely

Diatomaceous earth (DE) is a powder made of fossilized algae. Its sharp particles damage an insect’s waxy coating so it dries out. It works slowly (days, not hours) and only while dry, so it’s useless in wet spots. Buy “food grade” DE for home use, never pool-filter DE, which is processed differently and more hazardous to breathe. Apply a barely visible dusting with a bulb duster; thick piles are ignored by insects.

Wear a dust mask and gloves when applying diatomaceous earth and avoid breathing the dust, which irritates lungs and eyes. Apply it only in cracks, voids and behind appliances, not in open areas where kids or pets will walk through it or kick it into the air. Silverfish bait packets and boric acid products are pesticides: place them only where children and pets can’t reach, keep them away from food and food-prep surfaces, wash your hands after handling and follow the label exactly.

The equipment that helps

You don’t need much. A few traps to find and catch them, a way to lower humidity and a hygrometer to confirm it’s working.

A Govee Bluetooth hygrometer is a small add-on that tells you if your fix is working. For more options, see our picks for the best dehumidifier for basement spaces and the best small dehumidifier for bathrooms and closets.

What doesn’t work well

• Cedar and lavender sachets: they smell nice but have little evidence as a lasting repellent.
• Ultrasonic plug-ins: research on ultrasonic pest repellers shows little to no lasting effect on insects.
• General bug bombs (foggers): they don’t reach the cracks where silverfish hide, and they leave residue on every surface.
• Traps without drying the room: you’ll catch silverfish forever if humidity stays above 60%.

How to keep silverfish from coming back

• Keep indoor humidity between 30% and 50% year-round, especially in basements and bathrooms. A closet that smells musty needs extra help; see the best closet dehumidifier picks.
• Store paper, photos, documents and seasonal clothes in sealed plastic bins, not cardboard boxes.
• Don’t stack newspapers, magazines or grocery bags in basements or under sinks.
• Leave a small gap between furniture or bookcases and cold exterior walls so air can move.
• Caulk gaps around baseboards, pipes, window frames and bathtubs.
• Keep firewood, mulch and leaf piles away from the foundation, where outdoor silverfish can move in.
• Vacuum closets, shelves and baseboards regularly, and store dry food in airtight containers.

If your basement also smells damp, the same moisture that feeds silverfish can feed mold. Our guide to getting rid of a musty smell in the basement tackles both.

When to call a professional

Call a licensed pest control pro if you still see silverfish daily after four to six weeks of drying and trapping, if you find them in several rooms or floors, or if valuable books, documents, artwork or collections are being damaged. Pros can treat wall voids and attics with products that aren’t practical for homeowners. If the humidity comes from a leak you can’t find, standing water or mold covering more than about 10 square feet, bring in a plumber or mold remediation pro first, since that’s the real fix.

Frequently asked questions

Does one silverfish mean an infestation?

Not always. A single silverfish can wander in from outdoors, through gaps, or in cardboard boxes. But because they’re nocturnal and hide well, seeing one in daylight often means there are more nearby. Set a few sticky traps in the room for a week. If you catch several, treat it as an active population and start drying the room out.

Are silverfish harmful to humans?

No. Silverfish don’t bite or sting, and they aren’t known to spread disease. The problem is damage: they chew paper, book bindings, photos, wallpaper, starched clothing and dry food. Their scales and droppings can also add to indoor allergens for some people, so talk to a doctor if you notice symptoms.

What kills silverfish instantly?

Direct contact with a household insecticide labeled for silverfish kills them quickly, and a vacuum removes them instantly. But killing the ones you see does little if the room stays humid, because more will keep hiding in the walls. Traps, diatomaceous earth and baits work more slowly, and lower humidity is what actually clears them out.

Does a dehumidifier get rid of silverfish?

A dehumidifier is one of the most effective tools because silverfish need humid air to survive and reproduce. Keeping a basement or laundry room between 45% and 50% humidity makes it hostile to them within a few weeks. Pair it with traps and decluttering for faster results. Small thermoelectric units only help in tiny spaces like closets.

How long does it take to get rid of silverfish?

Most homes see a clear drop within two to three weeks once humidity is under control and traps are out, and most activity is gone in four to six weeks. Silverfish can survive a long time without food, so keep traps out for another month after the last catch to confirm they’re gone.

What smell do silverfish hate?

Cedar, lavender, cinnamon and citrus are often suggested, but evidence that scents keep silverfish away is weak. They may avoid a strongly scented spot for a while, then return. Your time is better spent on things that change their habitat: dry air, sealed storage, less clutter and sealed cracks.

Next step: learn how to keep the whole house drier with our guide on how to reduce humidity in house, or see our main guide on how to get rid of mice and other household pests.