How to Get Rid of Silverfish

How do you get rid of silverfish, step by step?

Silverfish are a moisture problem first. Ohio State University Extension says silverfish "live and develop in damp, cool places (preferring 75 to 95 percent relative humidity)," and that lowering the home's humidity with dehumidifiers and fans is often helpful ^[2]. University of California IPM adds that silverfish need a lot of moisture, so dehumidifiers and ventilation can make an area unsuitable for them ^[1]. Work in this order:

1. Find where they live. Check basements, laundry rooms, bathrooms (especially shower stalls), kitchens, closets and bookcases. Set a few jar traps or sticky traps overnight to see where most are caught.
2. Dry the air. Run a dehumidifier in closed, damp rooms and use exhaust fans after showers and laundry.
3. Fix the water. Repair dripping faucets, leaking pipes and sweating plumbing, and patch gaps around pipes and conduits ^[1].
4. Clear the clutter. Remove old newspapers, magazines, cardboard boxes, books and stored fabrics you do not need. Ohio State lists these as food and hiding places ^[2].
5. Seal food and clean. Keep cereal, flour and pet food in tight-lidded containers, and vacuum floors, shelves and cracks to remove crumbs, dust and the silverfish you see.
6. Trap and monitor. Keep jar traps out for a few weeks to catch stragglers and to check that numbers are falling.

Dry air does more against silverfish than any product: they cannot thrive where humidity stays low.

What attracts silverfish to your house?

Moisture, starch and undisturbed hiding places. UC IPM lists their foods as dry starchy foods, paper with glue or paste, book bindings, clothing starch, household dust, dead insects and fungi ^[1]. Ohio State adds wallpaper paste and notes that silverfish can contaminate dried foods and chew holes in clothing ^[2].

They often arrive with your belongings. Ohio State says silverfish and firebrats typically enter homes in food containers, furniture, old books, papers and old starched clothing. Because they grow slowly, "a large infestation in the house usually indicates a longtime infestation" ^[2].

Silverfish also have a close cousin, the firebrat, which likes the opposite climate. The table shows why the fix depends on which one you have:

	Silverfish	Firebrat
Color	Shiny silver or pearl gray	Mottled gray or brown, duller
Size	About 1/2 inch, up to 3/4 inch	About 1/2 inch
Favorite places	Damp, cool rooms: basements, bathrooms, laundry rooms	Hot spots: near furnaces, ovens, boilers, fireplaces, summer attics
Climate they like	High humidity (75 to 95 percent)	Above 90 F, humidity as low as 30 percent
Main fix	Lower the humidity and fix leaks	Seal and clean hot areas; target cracks near heat sources

Colors, sizes and climate from UC IPM and Ohio State University Extension.

Not sure it is a silverfish? The bug identifier tool can help, and our pest library has the profile.

Where do silverfish hide?

In dark, damp, undisturbed spots, and they come out at night. University of Minnesota Extension says silverfish are found indoors in cool, damp, dark places throughout the year, often in basements but also in many other rooms ^[3]. Ohio State notes they sometimes get trapped in bathtubs and sinks, because they cannot climb the slick sides ^[2].

Signs to look for include irregular holes or scraped areas on paper, book covers and wallpaper, tiny pepper-like droppings, and delicate, dust-like scales near damaged items. UC IPM notes that silverfish have weak jaws, so they scrape at paper rather than bite through it, and feeding often starts in one spot and spreads as unconnected holes ^[1]. Start your search in the bathroom and kitchen.

How do you make a silverfish trap?

A small glass jar is enough. UC IPM describes "small, glass jars covered on the outside with masking tape": silverfish climb up the rough tape, fall into the jar, and "can't climb back up the slick sides." Place the jars in corners and along edges where silverfish are likely to forage ^[1]. Sticky traps sold for cockroaches also work to detect and monitor them, and Ohio State says sticky traps can reduce small populations ^[2].

Empty the jars into a sealed bag or a toilet each morning, and move them to wherever you catch the most. If catches drop week after week, your drying and cleanup are working.

Do you need insecticide for silverfish?

Usually not. Ohio State states that "insecticides are generally not needed for management" of silverfish, and that sanitation and lower humidity are the main tools ^[2]. UC IPM warns that controlling large populations is "almost impossible" without removing dripping water and moist surfaces ^[1].

If silverfish persist after you have dried and cleaned, UC IPM describes these options:

• Dusts in dry cracks. Silica gel, diatomaceous earth and pyrethrin dusts "remain effective indefinitely in dry locations." Apply a thin, barely visible layer with a bulb duster into cracks, wall voids and behind baseboards; thick piles do not work, and wet dust loses effectiveness.
• Crack-and-crevice sprays. Small amounts of household products labeled for silverfish can be applied into cracks, baseboards, closets and pipe openings. Keep them out of sinks, drains, water and food.
• Not baits or foggers. Baits "aren't very successful" because silverfish tend not to feed on them, and "foggers aren't recommended" for silverfish and firebrats.

Read and follow the label. The label is the law. Use only EPA-registered products labeled for silverfish and for the place you are treating, keep children and pets away from treated areas and from any dust, and store products in their original containers out of reach. UC IPM says a properly applied product should show results within a few weeks; if not, silverfish are likely coming from untreated hiding places ^[1].

Without fixing the moisture, insecticides only buy time; dry air is the lasting treatment.

How do you keep silverfish from coming back?

Keep the house dry and keep their food and hiding places moving. UC IPM recommends periodically cleaning out closets, cabinets and storage containers, and occasionally moving the magazines, papers and books on your shelves, since undisturbed stacks give silverfish both food and shelter ^[1]. Routine cleaning also removes the dust and debris they feed on.

Watch what comes in, too. Because silverfish often ride into homes in cardboard boxes, old books, papers, used furniture and stored clothing ^[2], check those items before you bring them indoors, and unpack moving boxes promptly instead of storing the cardboard in a damp basement. Good habits to keep:

• Keep the dehumidifier running in basements and laundry rooms through humid months, and empty it often.
• Use exhaust fans during and after showers, and let bathrooms air out.
• Store papers and fabrics off basement floors, in sealed plastic bins rather than cardboard.
• Leave a jar trap or two out in problem rooms as an early warning.

Moving the stacks, drying the air and checking boxes at the door keep a small silverfish problem from becoming a long one.

When should you call a pest professional?

Silverfish do not bite people and are generally considered harmless; Ohio State calls them a nuisance that damages paper, food and clothing ^[2]. Call a licensed pest professional when:

• They keep showing up after several weeks of drying, decluttering and trapping. Ohio State advises using "a reputable, licensed pest control operator" for persistent problems or hard-to-find sources.
• They seem to come from inside walls. Ohio State notes that wall-void treatments may require drilling small holes, and some products are restricted to licensed applicators.
• You find hidden water damage, such as damp walls or a leak you cannot reach. A plumber or contractor may be needed before any pest treatment can work.
• Valuable papers, books or textiles are being damaged. Move them to dry storage in sealed plastic containers right away.

If you have other bugs in damp rooms too, see our guides to drain flies and roaches, or browse all How to Get Rid Of guides.