Silverfish: Pests or Just Unwanted Roommates? 2026

When you spot a silverfish in your bathtub, between the pages of a book, or under a rug, you usually don’t think much of it—beyond the initial surprise. They add a certain “character” to your home, but these pests can cause serious damage, ruining various organic materials high in carbohydrates and proteins. They tend to attack the glue behind wallpaper or in book bindings (even antique ones), cellulose, cereals, wool, cotton, silk, carpets, herbariums, museum collections, dried meat, furs, and more. In homes, it’s not easy to detect the damage and erosion caused by the mouthparts of these primitive insects over time, except in specific situations or severe infestations. Far more evident—and often irreversible—is the deterioration seen inside museums, archives, libraries, and historic buildings.

Let’s get to know them better… so we can fight them more effectively!

What Are Silverfish?

Silverfish belong to the order Zygentoma (formerly Thysanura). They have a tapered shape, long antennae, and a flattened body ending in three bristle-tipped filaments: the central one (caudal) is longer than the lateral ones (cerci). They are covered in scales, have no wings, and hide quickly in dark, quiet, humid places—though some species can survive and reproduce in drier environments. These insects are long-lived—adults can live up to three years—and juveniles are simply miniature versions of adults. Juveniles take many weeks to reach maturity, but adults continue to molt numerous times throughout their lives.

Common Species in Italy

In Italy, the species found in urban environments—not always easy to identify—belong to the family Lepismatidae: the classic silverfish or lepisma (Lepisma saccharina), the firebrat (Thermobia domestica), and some representatives of the genus Ctenolepisma.

Lepisma saccharina (Common Silverfish)

In homes, you’ll often find the common silverfish, 10–15 mm long, silvery-gray in color, with crepuscular/nocturnal habits. It prefers cool, fairly humid microhabitats, and its life cycle can range from 4 months to over a year, depending on environmental conditions.

Thermobia domestica (Firebrat)

In well-heated environments with temperatures of at least 30°C (86°F), the firebrat thrives. It’s about 10 mm long and characterized by tufts of dark bristles on its back, making it easy to identify. The female lays dozens of eggs near heat sources like radiators, fireplaces, boilers, and industrial ovens. Nymphs require at least 10–12 molts to reach maturity.

Ctenolepisma Species

Few people recognize Ctenolepisma species, which have varying coloration and are less common but still found in some Italian homes and buildings.

Are Silverfish Dangerous?

Silverfish are not directly harmful to humans—they don’t bite, sting, or transmit diseases. However, they can be destructive to household items. Their diet includes starchy materials, paper, glue, textiles, and even dried foods. Over time, they can ruin books, wallpaper, clothing, and carpets. In severe infestations, the damage can become costly, especially in libraries, museums, and historic buildings where irreplaceable items are stored.

How to Prevent and Control Silverfish

Prevention is the best strategy. Silverfish thrive in damp, dark spaces, so reducing humidity and eliminating hiding spots is key. Here are some practical steps:

• Reduce humidity: Use dehumidifiers in basements, bathrooms, and other damp areas. Fix leaks and improve ventilation.
• Seal entry points: Caulk cracks and crevices in walls, baseboards, and around pipes.
• Remove food sources: Store dry foods in airtight containers. Keep books, papers, and fabrics in dry, sealed storage when possible.
• Declutter: Reduce piles of paper, cardboard, and clothing where silverfish can hide.
• Use traps: Sticky traps can help monitor and reduce populations.
• Natural repellents: Cedar oil, diatomaceous earth, and boric acid can deter or kill silverfish. Sprinkle diatomaceous earth in cracks and behind appliances.

For severe infestations, professional pest control may be necessary. If you’re dealing with raccoons or other wildlife, check out our guide on the best poison for raccoons for effective solutions.

Are Silverfish a Sign of a Bigger Problem?

Silverfish often indicate high humidity or moisture issues in your home. While they can live in drier environments, they prefer damp conditions. If you see them frequently, it’s worth checking for leaks, poor ventilation, or other moisture sources. Addressing these issues not only helps control silverfish but also prevents mold and other pests.

FAQ About Silverfish

1. Can silverfish damage my home’s structure?

Silverfish don’t damage wood or structural elements directly, but they can ruin wallpaper, book bindings, insulation, and stored items. Over time, this can lead to costly replacements.

2. How do I know if I have a silverfish infestation?

Look for small, silvery insects in bathrooms, kitchens, basements, and attics. You may also find yellow stains, small holes in paper or fabric, or shed scales.

3. Are silverfish active during the day?

Silverfish are nocturnal and prefer dark, quiet places. You’re most likely to see them at night or when you disturb their hiding spots.

4. Do silverfish lay eggs in furniture?

Yes, silverfish can lay eggs in cracks, behind baseboards, under furniture, and in other hidden areas. The eggs are tiny and difficult to spot.

5. What’s the best way to get rid of silverfish naturally?

Reduce humidity, seal cracks, and use diatomaceous earth or boric acid in areas where they hide. Sticky traps can also help. For persistent problems, consult a pest control professional.

For more tips on managing pests in your home and garden, visit our yard and outdoors blog or check out home and garden tips for additional advice.