Silverfish eat paper because it contains two things they crave: cellulose and starch. These carbohydrates are a primary food source for silverfish, and anything made from paper, glue, cardboard, or paste is fair game. If you’ve found tiny holes or surface damage on books, documents, or wallpaper, silverfish are a likely culprit.
Why Silverfish Target Paper
Paper is made from plant fibers, which are rich in cellulose, a complex sugar that silverfish can digest. But cellulose isn’t the only draw. Silverfish also feed on the starch used to size and coat paper, the glue in book bindings, and the paste behind wallpaper. Essentially, a single book offers multiple food sources in one package: starchy pages, adhesive in the spine, and sometimes a cloth cover finished with additional starch.
They show preferences. Glazed or coated paper with a glossy, smooth finish appears to be especially attractive, likely because the coating contains more digestible starch. Cardboard is another target, and corrugated cardboard boxes are notorious for harboring silverfish colonies. Old magazines, photo albums (silverfish eat the coatings on photographs), envelopes sealed with adhesive, and stored documents in cardboard are all at risk.
What the Damage Looks Like
Silverfish don’t chew through paper the way mice do. Instead, they scrape the surface, creating a distinctive lacy, etched pattern. On book cloth and starch-sized paper, you’ll see shallow surface grazing rather than clean-cut holes. On thinner paper, their feeding produces small, irregular holes with uneven edges.
Beyond the physical damage, silverfish leave behind three telltale signs. Yellow stains from their excrement and body oils appear on paper surfaces and are extremely difficult to remove. Tiny translucent scales litter the area, because silverfish molt throughout their entire lives. And you may notice a faint peppered look from their droppings, which resemble small black specks. If you spot any combination of irregular holes, yellowish discoloration, and shed scales on stored paper, you’re almost certainly looking at silverfish damage.
Conditions That Bring Them In
Silverfish need moisture. They thrive in damp, warm spaces with temperatures between 71°F and 90°F, and they need relative humidity above 75% at higher temperatures. That makes laundry rooms, basements, bathrooms, and poorly ventilated closets ideal habitat. A box of old books stored in a humid basement is practically an invitation.
Temperature also affects how quickly they reproduce. Above 75°F, silverfish can develop from egg to adult in as little as 60 days. Below 50°F, that same development stretches to 500 days. This is why silverfish problems tend to escalate in warm, humid months and in climate-controlled buildings where conditions stay comfortable year-round.
They often arrive inside cardboard boxes, papers, and books brought in from already-infested locations. A single box of old files from a storage unit can introduce a colony into your home.
How to Protect Paper and Books
Humidity control is the single most effective step. Keep storage areas at or below 45% relative humidity. Humidity should never rise above 75%, which is also the threshold for mold growth. A dehumidifier in a basement or storage room can make the space inhospitable to silverfish while also protecting paper from moisture damage in general. Fans help by providing even air circulation and reducing pockets of dampness.
Storage materials matter. Never store books or documents long-term in corrugated cardboard boxes, which attract and shelter silverfish. Instead, use acid-free, lignin-free, buffered (alkaline) boxes designed for archival storage. These boxes also create a microclimate that buffers temperature and humidity swings, protecting paper from both pests and chemical degradation. Custom-fit alkaline book boxes are available from archival supply vendors, and simpler enclosures can be made inexpensively from 10-point alkaline cardstock.
For monitoring, sticky traps placed face-down on pennies (the slight elevation lets silverfish crawl underneath) are an effective, low-cost detection tool. Place them along baseboards and near bookshelves in storage areas. Screen floor drains and seal other entry points where insects could enter the room.
If books are already infested, freezing works. Place each book in a sealable polyethylene bag and freeze it at negative 20°F for at least 72 hours. This kills silverfish at all life stages without chemicals and without damaging most paper materials. Quarantine any newly acquired books, donations, or secondhand finds before adding them to your shelves, especially if they came in cardboard boxes or from a storage environment you can’t vouch for.
Other Materials Silverfish Eat
Paper is their most visible target, but silverfish feed on a surprisingly wide range of household materials. Cotton and linen fabrics, carpet fibers, curtain linings, and furniture upholstery are all potential food sources when they contain starch or are held together with glue. Synthetic fibers aren’t always safe either, as some contain starch-based sizing.
This broad diet is part of what makes silverfish so persistent. Even if you remove all paper from a room, they can survive on wallpaper paste, fabric starch, crumbs, or dead skin cells. Reducing humidity remains the most reliable way to make any space less appealing to them, regardless of what food sources are present.