Silverfish: Identification, Damage & Control Guide
By the Clark Pest Entomology Team | Last Updated: December 2, 2025
Key Takeaways
Silverfish are harmless to humans but destructive to property. These ancient, moisture-loving insects feed on starch and cellulose found in books, wallpaper, and clothing. They thrive in humid environments like bathrooms and basements. Prevention requires reducing humidity and sealing food sources.
Quick answer: If you spot a silvery, fish-shaped insect darting across your bathroom floor or find irregular holes scraped into your wallpaper or book pages, you likely have Silverfish (Lepisma saccharina). While they don't bite, they can live for years and slowly destroy your valuable paper and fabric items.
Visual ID: The Pest vs. The Damage
Silverfish are nocturnal and fast, so you might see the damage they cause before you see the insect itself. Here is what to look for.
The Pest: Silvery-gray scales, 3 long "tails" at the rear, moves like a fish.
Photo: Christian Fischer via Wikimedia Commons, CC BY-SA 3.0
The Damage: Irregular holes scraped into paper. Look for "etching" on surfaces.
Photo: Micha L. Rieser via Wikimedia Commons, CC BY-SA 4.0
What Do They Eat? (Almost Everything)
Silverfish are unique because they can digest cellulose and starch directly. This puts many of your household items at risk:
- Paper Products: Books, magazines, wallpaper, and important documents (especially the glue bindings).
- Fabrics: Cotton, linen, and silk. They are especially attracted to clothes with food stains or starch.
- Pantry Items: Flour, cereal, oats, and dried pasta.
Watch: Silverfish Habits Explained
Learn more about the life cycle of these prehistoric insects in this educational guide.
Video: Chrisado (Educational)
How to Get Rid of Silverfish (7 Steps)
Because they require high humidity to survive, controlling your environment is the best weapon against them.
- Dehumidify: Lower the humidity in your home (especially basements) to below 50%. Silverfish cannot survive dry air.
- Fix Leaks: Repair leaky pipes and faucets in bathrooms and kitchens.
- Remove Food: Store pantry items in airtight plastic containers, not cardboard boxes.
- Declutter: Get rid of stacks of old newspapers, magazines, and cardboard boxes in the garage/attic.
- Seal Cracks: Caulk gaps around baseboards, windows, and pipes where they hide during the day.
- Vacuum: Regular vacuuming removes food crumbs, eggs, and the silverfish themselves.
- Professional Treatment: If you see them in multiple rooms, you may have a widespread infestation in your wall voids that requires professional attention.
Clark's Expert Insight
"Silverfish are often a symptom of a bigger problem: moisture. If you suddenly see a lot of them in your bathroom or kitchen, check under the sink for a slow leak. You might solve your bug problem and save your cabinets at the same time."
Frequently Asked Questions (FAQs)
Do silverfish bite humans?
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No. Silverfish have very weak jaws designed for scraping paper, not biting skin. They do not bite or sting humans or pets, and they do not carry diseases.
Why are they in my bathtub?
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Silverfish often fall into bathtubs or sinks while foraging for moisture at night. Because the porcelain surface is too smooth, they cannot climb back out, so you find them trapped there in the morning.
Can silverfish cause allergies?
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Yes. Silverfish molt (shed their skin) throughout their lives. This dust from their scales and droppings can accumulate and trigger allergic reactions or asthma in some people, similar to dust mites.
Serving California and Northern Nevada
Our entomology team understands the unique pest pressures of our local region. From the humid valleys to the dry high deserts, we know where these pests hide.
Protect Your Books and Fabrics
Silverfish hide deep in wall voids and attics, making them nearly impossible to eliminate with DIY sprays. Clark Pest Control can target the source to stop them from eating your valuables.
Get a Free Silverfish Inspection