Silverfish are translucent, multi-legged insects that can scare the you-know-what out of you when found in your home. The good news is they won’t bite you — but they can cause significant damage to things like wallpaper, books, clothing, and food.
Here’s what you should know about these silvery pests that move like fish, including how to evict them from your home.
Silverfish belong to the species Lepisma saccharina. Entomologists believe silverfish are the descendants of insects that date back millions and millions of years. Other names people may have for silverfish include fish moths and urban silverfish.
Additional key aspects to know about silverfish include:
- They’re very small, usually about 12 to 19 millimeters in length.
- They have six legs.
- They’re usually white, silver, brown, or some combination of these colors.
- They like to live in humid conditions and usually only come out at night.
Scientists don’t believe silverfish bite people, as the insects have very weak jaws. They aren’t really strong enough to pierce a human’s skin. Some people may mistake an insect called an earwig for a silverfish — earwigs can pinch your skin.
Silverfish do bite into their food sources, though. Because their jaws are weak, it’s really more like a long drag or scrape. That’s where silverfish can damage your house. They can scrape their teeth against things like wallpaper, fabric, books, and other paper items. They tend to leave a yellow residue (fecal matter) in their wake.
Because silverfish are nocturnal and actually rather elusive, seeing these yellow markings or damage on paper or fabric in your house is usually the first sign that you have these insects.
Silverfish do leave behind their skin as they age — a process known as molting. These skins can collect and attract dust, which can trigger allergic reactions in some people.
An older laboratory study published in the journal Allergologia et Immunopathologia found that silverfish could stimulate allergic-type breathing problems in people who were allergic to common indoor allergens.
Silverfish aren’t known to carry pathogens or other potentially damaging diseases.
Do silverfish crawl in ears?
This belief stems from a rather unpleasant rumor that silverfish crawl into your ear and eat your brains or lay eggs in your ear canal.
Good news: They don’t do any of this. Silverfish are essentially very shy to humans, and are really trying to avoid you at all costs. They don’t eat blood, and are more interested in your paper products than anything on your body.
Are silverfish harmful to pets?
Just as they can’t bite humans, silverfish can’t bite pets. They won’t poison your pet if it eats them. However, eating silverfish could give your dog or cat a pretty significant stomachache.
Silverfish eat cellulose. That’s the starchy sugar present in paper products as well as dead skin cells like dandruff. They’re attracted to damp, dark spaces with plenty of cellulose to eat.
Even though they like to eat, silverfish can go long time periods without eating. They also reproduce quickly and can live for several years. This means a few silverfish can quickly turn into an infestation of silverfish that can damage your home.
If you’ve spotted a silverfish or lots of silverfish, it’s time to go into extermination mode. You can start by sealing up areas of your home where air, moisture, and pests can get in.
You can also use dehumidifiers in areas like the basement to reduce the moisture silverfish love so much.
You have some options when it comes to actually killing silverfish:
- Spread out diatomaceous earth (DE). This is a product you can purchase at most home improvement stores that contains ground-up fossils that have jagged edges. Essentially, when a silverfish tries to move through the stuff, it kills them. You can sprinkle DE under your sinks, in cupboards, and along the areas of your home where the walls meet the floor. Leave it on for 24 hours, then vacuum to remove.
- Place sticky insect traps around your baseboards and corners of your home. Place something sweet or papery on the sticky paper, and the silverfish will likely come to it.
- Sprinkle boric acid on the same areas in your home as you would DE. The catch here is that boric acid could harm children and pets if they accidentally ingest it. So avoid this option if a person or pet may come in contact with it.
You can also hire a professional exterminator. They have access to chemical baits that can kill silverfish if traditional options like boric acid have failed.
Ensuring your home is well-sealed and maintained can keep silverfish and a lot of other pests out. Some ways to accomplish this include:
- Fill in gaps in your foundation or basement walls with liquid cement, which can be purchased at most hardware stores.
- Place gravel or a chemical barrier between the ground outside and the basement walls of your home. The gravel, as compared to mulch, keeps out moisture. Because silverfish are attracted to moisture, this can help prevent them.
- Keep your home neat and tidy. Seal food in airtight containers, and avoid leaving a lot of paper products in piles on the floor.
- Contact an exterminator or pest control expert to rid your home of insects and rodents that can chew on walls, door frames, or other areas that allow silverfish entry into your home.
If you aren’t sure where to begin, a professional pest management company can make recommendations on changes to help keep pests like silverfish out.
Silverfish won’t bite you or crawl in your ears while you sleep at night. But they can damage wallpaper, food, and other paper products in your home. And if silverfish can get in, it’s likely other pests can too.
Keeping your home sealed and well-cleaned can help keep silverfish and other pests out.