How to Get Rid of Silverfish (DIY Guide)

Silverfish (Lepisma saccharina) are about ½–¾ inch long, wingless, and covered in silvery scales. They have three long tail-like appendages and two antennae. They move in a distinctive fish-like wriggling motion — hence the name.

They're nocturnal and fast, which is why you usually only see them when you flip on a light in the bathroom at night and they scatter. They thrive in humid environments (75%+ relative humidity) and feed on starchy materials: paper, glue in book bindings, wallpaper paste, natural fabrics (cotton, silk, linen), cardboard, and even the sizing on clothing.

Silverfish are a humidity indicator pest — if you have them, your home likely has moisture issues somewhere. Solving the humidity problem often solves the silverfish problem.

• Dehumidifier — For reducing humidity in problem areas. This is the most impactful investment.
• Diatomaceous earth (food-grade) — For treating cracks and crevices where silverfish hide.
• Sticky traps — For monitoring and reducing the population.
• Caulk — For sealing entry points and hiding spots.
• Boric acid powder — For treating hidden areas (behind baseboards, under sinks).
• Plastic storage bins with lids — For protecting books, documents, and clothing.

Step 1: Reduce Humidity

This is the single most effective step. Silverfish need high humidity to survive. Target these areas:

• Use a dehumidifier in basements, bathrooms, and laundry rooms.
• Run bathroom exhaust fans during and after showers for at least 15 minutes.
• Fix any leaking pipes or faucets.
• Ensure proper ventilation in attics and crawl spaces.
• Open closet doors periodically to allow air circulation.

Getting humidity below 60% makes your home significantly less hospitable to silverfish.

Step 2: Remove Food Sources

Store paper goods, books, and important documents in sealed plastic containers. Don't leave stacks of newspapers, magazines, or cardboard boxes in storage areas. If you have valuable books, keep them in climate-controlled areas.

Step 3: Apply Diatomaceous Earth

Lightly dust food-grade DE in areas where silverfish hide:

• Behind baseboards (you can puff it into the gap between baseboard and floor)
• Under sinks and around pipe penetrations
• In closet corners and along shelving
• In attic spaces and along the attic floor near walls
• Inside stored boxes (before sealing them)

DE works by damaging the silverfish's waxy outer coating, causing them to dehydrate. It's safe for people and pets but can be messy — apply sparingly in areas that are out of sight.

Step 4: Set Sticky Traps

Place sticky traps along baseboards in bathrooms, basements, closets, and under sinks. Check them weekly. They help you monitor whether your efforts are working and where activity is concentrated.

Step 5: Seal Cracks and Crevices

Caulk gaps around baseboards, pipe penetrations, and window/door frames in areas where you've seen silverfish. This reduces hiding spots and entry points.

• Maintain low humidity — Keep indoor humidity below 60% using dehumidifiers, exhaust fans, and proper ventilation. This alone prevents most silverfish problems.
• Store paper goods in sealed containers — Books, documents, and photos should be in plastic bins, not cardboard boxes in damp basements.
• Vacuum regularly — Especially in closets, under beds, and along baseboards. This removes silverfish, eggs, and the starchy debris they feed on.
• Don't stack old newspapers and magazines — These are silverfish buffets. Recycle them or store in sealed bins.
• Check items before bringing them inside — Silverfish can hitchhike in cardboard boxes, old books, and stored items from garages or storage units.

• Ignoring the humidity problem — You can kill every silverfish you see, but if your bathroom humidity is at 80%, more will come. Fix the environment first.
• Over-applying diatomaceous earth — If you leave thick piles, silverfish will simply walk around them. A barely-visible dust coating is more effective because they walk through it unknowingly.
• Storing valuable items in cardboard in damp areas — If your basement is humid, silverfish will find and damage paper items stored in cardboard boxes. Switch to sealed plastic bins.
• Expecting instant results — Silverfish reproduce slowly compared to roaches or ants (they live 2–8 years and lay eggs in small batches). Reducing the population takes weeks, not days. Be patient with your treatment approach.