Silverfish are small and basically harmless to humans. Silverfish don't bite or sting, and they're not known to carry diseases. However, a silverfish infestation can be harmful to your house.
In large numbers, silverfish can damage textiles (including clothing, rugs, and upholstery) and soft building materials. Vintage clothing and rugs can be particularly vulnerable because they're usually made of natural fibers that silverfish like. Plus, just as moths eat wool clothing, silverfish love to munch on cashmere sweaters and velvet jackets. Books or paper files might also get destroyed; silverfish like the glue in older books. They also eat household glue and certain kinds of paint. Furthermore, in some cases, the presence of silverfish can exacerbate sensitivity to other allergens in the home.
A few silverfish can maintain a good insect equilibrium in the home. They eat predatory bugs, including spiders, and they will even eat their own dead. So you shouldn't necessarily kill silverfish if you see just one bug. However, if you're seeing lots of them, it's likely you have a silverfish infestation on your hands that needs remedying. Here's how to get rid of silverfish.
What Are Silverfish?
Silverfish (Lepisma saccharina) are small, wingless, six-legged insects that reach about 3/4-inch long. Their solid silvery gray color looks metallic and their movements are somewhat fishlike. Another name for them is fish moths. Silverfish are also sometimes called bristletails because of the three tail-like tendrils on their rear sections.
Signs of a Silverfish Infestation
While silverfish may be small, their damage can be serious and they can grow in numbers quickly. So it's important to identify and address an infestation immediately before the destruction spreads. Here's how to know if you have a silverfish infestation:
- Feeding marks, such as irregular holes on fabrics and other surfaces
- Yellow stains or feces (which appear like tiny black pepper pellets) on surfaces
- Regular sightings of silverfish bugs
Note that silverfish don't like bright light, so you might not see them by day unless it's cloudy.
6 Ways to Get Rid of Silverfish
Once you discover you have a silverfish infestation, take action as soon as possible to get rid of them. You will have to systematically clean all the surfaces in your home, including clothing and bedding.
Thoroughly wash all clothing, bedding, and other textiles (such as curtains). Shampoo carpets and clean area rugs according to the care label. If shampooing a carpet isn't possible, sprinkle it with diatomaceous earth and then vacuum. Then, apply cedarwood spray. Vacuuming upholstered furniture, including under cushions, is also a good idea.
Sprinkle Diatomaceous Earth
Diatomaceous earth is a fine powder that contains fossilized diatoms (algae). The particles have jagged edges that are only mildly abrasive to humans but can be deadly to insects. Diatomaceous earth will cut into silverfish as they crawl over it, and it will absorb moisture, causing them to dehydrate and die. Sprinkle it on your floors, especially in areas where you frequently see silverfish. Leave it for 24 hours, making sure it stays dry, and then vacuum it up. Keep young children and pets away from the area.
Trap Them in Glass
Glass containers can make for easy and effective silverfish traps. Silverfish can't climb on glass, so one method of trapping them for removal is to put tape on the outside of a glass jar containing starchy food. Once they enter, they won't be able to get out. Put the lid on the jar, and remove the silverfish from your home.
Trap Them in Paper
Another makeshift silverfish trap is to roll up a newspaper and spray it with water. Silverfish will crawl into it and make a cozy home. Then, after a few days, discard the newspaper or burn it.
Use Boric Acid
Boric acid can be used just like diatomaceous earth. It's a pesticide that will kill silverfish instantly. However, it can be toxic to children and pets, so it's not always a desirable method.
Hire an Exterminator
If your DIY methods to get rid of silverfish haven't worked or you have a severe infestation, it's likely time to bring in a professional. They should have experience dealing with cases like yours.
What Causes a Silverfish Infestation?
There are several factors that can cause silverfish in your home. Silverfish are attracted to moist, humid areas of the home. This is why you often see silverfish in bathrooms, kitchens, and basements. They might also congregate in other areas where water is getting in, such as by a leaky roof or window frame.
Moreover, silverfish are attracted to dust, grains, and dried meat products, such as jerky and pet food. Their main food source is cellulose, a starchy sugar substance found in paper products, some fabric fibers, and in skin cells (such as dandruff). If you have stacks of old books or magazines that gather dust in your home, there's a good chance you'll get silverfish.
How to Prevent Silverfish Infestation
There are a few good and safe ways to prevent an infestation of silverfish bugs in the home.
One of the best ways to prevent a silverfish infestation is to make sure there is no unchecked humidity or moisture in the home. Ensure good bathroom ventilation, and open windows when possible to circulate fresh air. Heated towel racks can help cut back on moisture in the air. A dehumidifier is also a good idea. Plus, fans to keep air flowing can help to reduce humidity. And silica gel packets placed in drawers or cupboards can help to reduce moisture, as long as they are out of the reach of kids and pets.
It's also important to dust and/or vacuum regularly to reduce the amount of dust that silverfish love to feed on. If you have wood floors, sweep and damp mop with an oil-based soap. Shake out your rugs regularly, outside if possible.
Cut Back on Clutter
Don't let cardboard recycling build up; silverfish are attracted to the glue. In addition, get rid of old books or clothes you're never going to use again.
Seal Grain Products
Keep all grain products sealed in glass jars or ziplock bags; this includes pasta, rice, cereals, and flour. Clean up food particles that fall on the floor or counter or that escape into the pantry or cupboards.
If you have gaps in any of your window frames, consider caulking to seal them. Caulking is also a good choice for any random spaces in the attic exposed to the outside where silverfish might find a way inside.
Apply Essential Oils
Silverfish dislike the smell of cedar, so one good natural preventive method is to make a spray using cedarwood essential oil (10 drops to 4 ounces of water, shake gently before each use). Spray in damp corners and/or in closets and near bookshelves. You can also spray down your rugs and upholstery. Another method is to drop the essential oil onto several cotton balls in an open glass container (such as a votive candle holder), and place it where the scent will be diffused through the air. Cedarwood shavings can also be used.
Silverfish also dislike the smell of bay leaves. Crush dried bay leaves, and tie them up in muslin bags to place in drawers, closets, and corners.
How long do silverfish live?
Silverfish can live up to eight years and can reproduce frequently in their lifetime.
Biochemical and molecular biological aspects of silverfish allergens. Protein Pept Lett.
Bristletails (Silverfish and Firebrats). Penn State Extension.
R.E.D. Facts: Boric Acid. US EPA.