Getting rid of silverfish requires two things: removing the moisture they depend on and eliminating their food sources. Kill the ones you see with traps or dust treatments, but lasting control comes from making your home inhospitable to them. Without high humidity, silverfish can’t reproduce or survive long-term.
Why Silverfish Are in Your Home
Silverfish are small, wingless insects with silvery-gray scales and three tail-like appendages at the rear. They move in a wriggling, fish-like motion and are almost always active at night, which is why you can have a sizable population before you ever spot one. They prefer temperatures between 71°F and 90°F and need relative humidity above 75% to thrive at warmer temperatures. Laundry rooms, bathrooms, basements, and kitchens are their favorite spots.
They eat starch, cellulose, and protein. In practical terms, that means books, magazines, wallpaper, wallpaper paste, glue bindings, cardboard boxes, cotton and linen clothing, silk, and anything with food stains or starch residue. They scrape irregular holes into paper and leave a distinctive “etching” pattern on surfaces. If you’ve noticed tiny holes in stored papers or small yellowish stains on fabric, silverfish are a likely culprit.
Silverfish also molt throughout their entire lives, shedding tiny scales that accumulate as dust. This shed material, along with their droppings, can trigger allergic reactions and asthma symptoms in sensitive people, similar to dust mites. Their presence can also attract carpet beetles and other pests that feed on the same materials.
Cut the Humidity First
This is the single most effective step. Silverfish eggs hatch in 19 to 32 days under favorable conditions, and the insects actually crowd together to regulate humidity around their eggs and young. Drop the moisture level in your home and you disrupt their entire reproductive cycle.
Run a dehumidifier in your basement, crawl space, or any room where you’ve seen silverfish activity. Aim to keep indoor humidity below 60%, and ideally closer to 50%. Fix leaky pipes, improve ventilation in bathrooms with exhaust fans, and avoid drying clothes indoors without ventilation. If your bathroom fan doesn’t vent to the outside, it’s just recirculating moist air. Check that dryer vents are properly connected and not leaking warm, humid air into the house.
In crawl spaces, a vapor barrier over exposed soil makes a significant difference. Even small improvements in airflow, like opening a window or adding a vent fan in a damp storage area, can shift conditions enough that silverfish stop breeding there.
Remove Their Food Sources
Silverfish can survive a long time without eating, but removing easy food sources forces them to move and makes traps and treatments more effective. Store books, old magazines, and important documents in sealed plastic bins rather than cardboard boxes. Cardboard itself is a food source, so replacing cardboard storage with plastic is doing double duty.
Keep dry pantry goods like flour, cereal, pasta, and pet food in airtight containers. Vacuum regularly in closets, under furniture, and along baseboards where dust and debris accumulate. Pay special attention to clothes with food stains or starch. Launder or dry-clean items before storing them for long periods, and use sealed garment bags for anything you won’t wear for a while.
If you have old wallpaper that’s peeling, the exposed paste underneath is a magnet. Either re-glue it or remove it entirely.
Diatomaceous Earth for Active Infestations
Food-grade diatomaceous earth is one of the most effective non-chemical treatments for silverfish. It’s a fine powder made from fossilized algae that works mechanically, not chemically. The tiny particles absorb the oils and fats from the insect’s outer shell while their sharp edges abrade it, causing the silverfish to dehydrate and die. It doesn’t need to be eaten to work. Any silverfish that walks through it is affected.
Apply a light dusting in cracks along baseboards, behind appliances, inside wall cavities accessed through outlet covers (turn off the breaker first), under sinks, and in the back corners of closets and cabinets. The key word is light. A barely visible layer works better than a thick pile, because silverfish will walk around heavy deposits. It remains effective indefinitely as long as it stays dry and undisturbed, so areas behind furniture or inside wall voids are ideal.
Use food-grade diatomaceous earth specifically. The pool-grade version is chemically different and not safe for household use. Wear a dust mask during application to avoid inhaling the fine particles, which can irritate your lungs.
Traps and Baits
Sticky traps placed along baseboards, in closets, under sinks, and near bookshelves will catch silverfish that are actively foraging at night. They won’t eliminate an infestation on their own, but they serve two purposes: they reduce numbers and they show you exactly where activity is concentrated, so you can target those areas with other treatments.
You can make a simple DIY trap by wrapping the outside of a glass jar with masking tape (so silverfish can climb up) and placing a small piece of bread or a cracker inside. They climb in and can’t climb back out on the smooth glass. Place several of these in problem areas and check them every few days.
Commercial silverfish bait packs containing boric acid are available at most hardware stores. Place them in dark, undisturbed spots where you’ve seen activity or damage. Keep them away from areas where children or pets can reach them.
Chemical Treatments for Severe Problems
If humidity control, food removal, and diatomaceous earth aren’t enough, residual insecticide sprays can help. Products containing bifenthrin (sold under names like Ortho Home Defense) work by disrupting the nervous system of insects on contact. Apply along baseboards, door frames, window frames, and around pipe entries. These sprays leave a residual barrier that continues killing insects for weeks after application.
Focus on entry points and transition zones: where walls meet floors, around plumbing penetrations, and along the edges of rooms rather than open floor areas. Silverfish travel along edges and through cracks, so that’s where the product needs to be. Follow label directions carefully, ventilate treated rooms, and keep pets and children away from freshly treated surfaces until they’ve dried completely.
Seal Entry Points
Silverfish enter through gaps around pipes, cracks in foundations, spaces under doors, and openings around window frames. Caulk visible cracks along baseboards and around plumbing penetrations. Use weatherstripping under exterior doors. Screen or seal any gaps where utility lines enter the house.
Inside the home, sealing cracks also reduces the number of sheltered hiding spots where silverfish lay eggs. Even small efforts here compound over time, especially when combined with humidity reduction.
When DIY Methods Aren’t Enough
Silverfish reproduce steadily, and a small population can become a large one without much warning. If you’ve been working on humidity, food sources, and treatments for several weeks and still see regular activity, or if you’re finding damage to books, clothing, or stored items, a professional treatment is worth considering. Pest control companies typically start with a thorough inspection of dark, humid areas, then use targeted treatments combined with crack sealing, humidity recommendations, and monitoring traps placed in kitchens, bathrooms, utility rooms, and garages to track activity over time.
Professional treatment is also the faster option if you’re dealing with silverfish in wall voids or attic insulation, where DIY access is limited. The long-term fix is still environmental: until humidity and food sources are addressed, any treatment is a temporary measure.