Do Silverfish Bite?

All homeowners know the feeling—you’re just getting ready to crawl into bed when you notice a particularly creepy visitor climbing your wall or scurrying into the shadows. 

Silverfish are one of the U.S.’s most common and most creepy species of crawlers. They’re stealthy, only come out at night, and are strangely shaped, like fish with antennae and bristletails. Plus, they might leave mysterious yellow trails or bites on your belongings.

But you might be left wondering—are silverfish harmful? Do they bite humans? Should I actually be afraid of them? Read on for the lowdown on silverfish, how to handle them, and whether they bite.

Key Takeaways

• Silverfish are nocturnal, flightless insects resembling fish that feed on household objects like paper and sugar.

• Silverfish don’t bite, but they can be a nuisance and may damage your belongings.

• There are steps you can take to prevent a silverfish infestation, like sealing entry points, setting traps, or diffusing silverfish-repellent scents. But if you think your silverfish problem is serious, it’s best to call an exterminator early.

What Are Silverfish?

Silverfish are flat, carrot-shaped, wingless insects that resemble small fish. They’re fast runners, so they’re often only seen when running from a disturbed hiding spot. 

They also feed on cellulose-rich (sugary, starchy) household objects like dust, dandruff, flour, cotton, linen, wallpaper, cardboard, and book bindings.

Silverfish, a sort of sister pest to firebrats, are found throughout the U.S., but they’re most fond of damp, moist, humid, and temperately cool conditions (so they’re most common in the South and from the Midwest to the West Coast). 

This also means they’re often found in basements, attics, garages, laundry rooms, closets, and storage areas full of their favorite foods (i.e. books, cardboard, linens).

The presence of silverfish typically indicates too much moisture, either in the local climate or in your home. Silverfish are cosmopolitan pests, meaning they can be found almost anywhere on Earth, and are nocturnal.

Do Silverfish Bite?

No, silverfish do not bite. 

These pests have weak jaws, so even if they attempted to bite a human, it would feel like more of a gentle scraping motion and wouldn’t pierce skin. If you notice silverfish “bites” on food sources like cardboard or wallpaper, it’s because silverfish have gently scraped their teeth along an object while eating. 

But silverfish don’t feed on blood, are known to be extremely shy around humans, and will avoid us at all costs. (This means that the old wives’ tale about silverfish crawling into your ear is also fiction.)Silverfish will not bite your pets either.

How Do Silverfish Get In Your Home?

Silverfish typically sneak in through cracks, holes, and gaps in exterior walls. They’re attracted to warmth and moisture, so if your home has any open cracks and crevices that are the result of moisture damage, especially near pipe openings, these are the most likely front doors for silverfish. Consider investing in a dehumidifier and be sure to keep your home dry.

Silverfish can also get into your home by hitching a ride with an infested food source, like a bag of dry food, a cardboard box, or a container of paper or fabric. Higher temperatures speed up the silverfish breeding cycle, so if you’re stuck with a stowaway in the summer, you may soon have a bigger problem on your hands.

Any silverfish that make their way into your home, with the exception of far-traveling stowaways, likely came from the soil near your house.

Signs of Silverfish Damage?

The first telltale sign of silverfish damage are yellow stains (either a trail or yellowish dust) from excrement that they leave behind (particularly on or near food sources, like books, cellophane, or synthetic-fabric clothing). You might also notice fecal matter resembling peppercorns.

You might notice scratches (etches or notches along edges) or holes on an object that’s been a silverfish’s dinner, such as newspaper or cardboard boxes. Even fabrics including linen, cotton, silk, and leather can be scratched up by a hungry silverfish. 

Shed skins are another omen of a silverfish infestation—these opaque, metallic skins are shed throughout this insect’s life cycle.

How to Get Rid of Silverfish

While silverfish are a nuisance (they’re creepy crawlers that may damage your belongings or cause mild allergic reactions), they’re not dangerous. However, if you’ve noticed a critter or two around your home, there are steps you should take to avoid a full-blown infestation. Below is a breakdown of the most effective ways to prevent silverfish.

Traps

Silverfish are notoriously fast runners and difficult to catch by hand, but there are silverfish traps on the market that may do the trick. Most are sticky traps (since silverfish eat paper and glue, it’s the perfect bait), but there are also repellent diffusers and boric acid traps available online or at hardware stores, or you can DIY a sticky pitfall by wrapping a jar in masking tape and placing bit of cereal as bait inside (the glass walls are too slippery for silverfish to climb).

Seal Entry Points

Sealing entry points is the most crucial way to prevent silverfish from ever entering your home. Be sure to inspect your home carefully for any moisture-related damage, and keep it warm, dry, and well-lit. Keep doors and windows sealed shut when possible and fill any open crevices with caulk or spackle. Inspect objects that might be infested before bringing them into your home (i.e. used books, cardboard boxes). 

Reduce Clutter

Reducing clutter not only reduces the amount of food sources out in the open for silverfish to feast on, but also reduces the number of places for them to hide unnoticed. Vacuum often, and seal up silverfish snacks like flour, sugar, and potatoes. File away papers and books in a dry place. Keep linens dry and wash them often.

Diatomaceous Earth

Diatomaceous earth is a crumbly white powder made from the remains of ancient fossilized algae. DE is absolutely deadly to any insect with an exoskeleton, producing the effect of death by a thousand cuts or walking on glass. It also causes an internal shutdown if eaten, and robs silverfish’s bodies of the moisture they seek, causing them to dry up and die. Sprinkle diatomaceous earth in places that you think silverfish may appear overnight and vacuum up the remains in the morning.

Boric Acid

Boric acid is a common pesticide that’s poisonous to many insects if eaten. It can also scratch or damage exoskeletons if a bug comes into contact with it. It’s found in many poison-filled silverfish traps, or can be spread around your home on its own in liquid, powder, or tablet form.

Essential Oils

The scent of certain essential oils may act as a natural repellent for silverfish. For instance, diffusing cedar essential oil (or adding a few drops onto cedarwood blocks or balls) is a known way to repel these insects.

Other scents that repel silverfish include orange, clove, cinnamon, lemon, peppermint, rosemary, bay leaf, and lavender.

Cinnamon

Since the scent of cinnamon is a natural silverfish repellent, try sprinkling ground cinnamon or placing cinnamon sticks in areas where you’ve noticed some creepy crawlers. You can also add a few drops of cinnamon oil to these areas or diffuse it throughout your home.

Professional Pest Control for Silverfish

Silverfish multiply fast, particularly in hot and humid conditions. It’s best to catch an infestation early. Contact a pest management professional if you notice any of the aforementioned signs of infestation (live silverfish, yellow stains, droppings, or molted skin). 

While silverfish are not harmful or poisonous, they can be a serious nuisance and may damage your belongings or leave droppings on your clothes or in your food. A pest control service can nip the problem in the bud fast, giving you the peace of mind that your silverfish infestation won’t return anytime soon.