Silverfish are teardrop-shaped, silver-gray insects that thrive in damp, dark spaces and feed on starches, paper, and fabrics. Common in Whidbey bathrooms, crawl spaces, and storage areas, they signal excess humidity and can damage books and stored goods.
How to identify silverfish
About 1/2 inch, silvery-gray, teardrop-shaped, with three long tail filaments and a wriggling, fish-like movement. They are wingless and fast.
Behavior & season on Whidbey & Fidalgo
They need high humidity and hide in bathrooms, crawl spaces, attics, and storage, feeding at night on starches, glue, paper, and fabric. Populations build slowly wherever dampness persists.
Why silverfish are a problem
They do not bite or transmit disease, but they damage books, photos, wallpaper, and stored fabrics, and their presence reliably indicates a moisture problem worth correcting.
Signs of silverfish activity
- Silvery, fish-shaped insects in bathrooms or storage
- Irregular holes or grazing on paper and fabric
- Yellowish stains or scales on stored items
- Activity in damp, undisturbed areas
How Salty Dog treats silverfish
We treat harborage and reduce the humidity feeding them, targeting the damp voids and storage areas where they hide and breed. Learn more about our Silverfish Control service, or browse the full Pest Library.
Reviewed by Matthew — Salty Dog Pest Control. WSDA-licensed structural pest applicator (License #101709). Veteran- and family-owned, serving Whidbey Island, Fidalgo Island, and west Skagit County.
Frequently asked questions
What attracts silverfish?
Moisture and starchy materials — paper, glue, and fabrics in humid, dark spaces. Lowering humidity is central to controlling them.
Are silverfish harmful?
Not to people, but they damage books, photos, wallpaper, and stored textiles, and they indicate an underlying moisture issue.
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