Are Silverfish Bad? The Answer Surprised Me!

Even if you love all creatures large and small, there’s something about silverfish that triggers recoil in us humans. It’s almost instinctual, as if you just know on a genetic level that this animal is bad news. It moves very fast, it writhes like a serpent and those three spikes on its lashing tail… what the heck?

So are silverfish really dangerous? Will they nibble your feet off while you sleep? Lay their eggs in your brain? Calm down. The truth is, silverfish are quite harmless for humans.

Let’s find out what sort of creature we’re dealing with. 

Are Silverfish Bad?

First, the short answer to the most critical question, since you’re probably looking this article up after you’ve run into a silverfish in your home. 

Silverfish are not malicious, and they do not go out of the way to do you harm. To be sure, their presence in your home isn’t a good thing, but it all has to do with their placement. 

When a dandelion is in a meadow, it’s a wildflower. When a dandelion is in your garden, it’s a weed. There’s nothing inherently bad about the plant, but it’s better off in some environments than others. Now for the more granular questions…

What Are Silverfish?

Silverfish are wingless insects and are a very ancient species. They’ve been scuttling around the world for more than 400 million years and are pretty much the same now as they were when they shared the world with dinosaurs.

 They are extremely hardy and have survived the worst of times. It comes as no surprise, then, that silverfish are prehistoric in appearance. Just as their name suggests, they are covered in tiny scales which make them look silver.

But the real source of the name comes from the way that they move. When running along a horizontal surface, they tend to move in a serpentine fashion and they look like a fish swimming. Fascinating in theory. Horrifying in practice.

It’s that strange movement that freaks us out, and it also doesn’t seem to make sense that they don’t have any wings. 

Are Silverfish Harmful to Humans?

As unsettling as they are to behold, silverfish are 100% harmless. That is, silverfish will not bite humans. Some of their molting may trigger allergic reactions in some people, but for the most part they are clean animals that do not spread diseases.

The only way a silverfish could spread disease is if they crawl around in your trash and spread bacteria by crawling on other surfaces where you’re used to eating.

Despite what some well-meaning people will tell you, silverfish do not crawl into people’s ears and burrow into their brains or lay eggs there, or anything else. Neither are silverfish blood-eating insects, so they’re not inclined to bite.

Are Silverfish Harmful to Pets?

The strange looks and moves of silverfish might terrify you, but they’re fascinating to your pets. Ingesting bugs and animals, even fleas, is among the ways that pets can pick up a wide range of parasites, including worms. 

Well, pet-lovers rejoice. Silverfish aren’t going to pass on any diseases or pathogens if they are eaten by your pets. Nor are your pets in any danger of being bitten, stung, or poisoned by silverfish. 

Worst case scenario, your cat might gift you with a small, shiny, wriggling gift.

Are Silverfish Harmful to Your Home?

If the fact that silverfish don’t bite is the good news, then the bad news is that they pose a significant threat to your personal belongings. Silverfish eat anything that contains starch or polysaccharides.

This means items such as paper, photos, wallpaper glue, book bindings, and more are on the menu and at risk of being damaged. They also have an appetite for organic material such as hair and cotton and wool. So yes, that means that your clothes are also at risk of being an all-you-can-eat buffet.

While roaches can be eliminated simply by removing their sources of food and water, silverfish are a little more resilient. These prehistoric creatures can survive for well over a year without food. So you can get rid of all the wallpaper, books, and clothes in your home and you can still be seeing silverfish after a year.

Are Silverfish as Bad as Roaches?

By American-cockroach.jpg: Gary Alpertderivative work: B kimmel (talk) - American-cockroach.jpg, CC BY 2.5,

Neither pest is desirable in your home. But silverfish get slightly higher marks than cockroaches just for the simple fact that they do not spread diseases or pathogens. And silverfish are less likely to trigger your allergies.

Silverfish might even be more tenacious than cockroaches. Cockroaches will eventually pack up and move on to easier pickings when their food and water sources are eliminated. As noted, silverfish aren’t picky about their eating habits, and they can survive for well over a year without food as long as they have water. 

What Does the Presence of Silverfish in Your Home Really Mean?

The presence and problems that stem from a silverfish infestation are a big matter, but it’s one piece of a bigger puzzle.  Silverfish in your home is actually a message to you about the condition of your living space.

Silverfish need moisture and high temperatures in order to survive. They’re the most comfortable in high humidity levels. So if silverfish are able to comfortably colonize your home, then there is moisture someplace you don’t know about. The fact that they’ve been able to get into your home likely means that there is a hole somewhere in your home that has been created by water damage.

Leaky pipes, damage in the foundation, clogged gutters, are all potential water problems that could be in some invisible corner of your home.

Once inside, they will congregate and make their home in places where the moisture is going to stay, such as bathrooms, basements, kitchens, and other high-moisture areas.

Are Silverfish Good For Anything?

When they’re in your home and eating your precious books and photos, it’s hard to think of silverfish as having any redeeming qualities. But like the example of the dandelion in the meadow, silverfish have an important role to play in the wild. 

The precious books, clothes, and other wood-based items around the home are no different than the untold tons of rotting wood and decaying organic material in the wild. 

If you watch them long enough, you would notice that they also eat things that you definitely don’t want around your house, such as dandruff and dead insects. 

Silverfish are part of nature’s team of sanitation workers that get rid of decaying and rotting material and breaking dead wood down into basic elements that nourish the Earth.

They’re in a similar category as earthworms and pill bugs in that they are vital to converting natural garbage into usable elements for the soil. So silverfish have no place in your home, but they play a very important role in the natural world.

How Do You Get Rid of Silverfish?

Anything short of calling a professional exterminator is sure to be a long, difficult fight against the presence of silverfish in your home. That said, there are some things you can do to discourage their presence and keep them from getting too comfortable.

Since they need moisture in order to thrive, a step in the right direction is setting up a dehumidifier, especially in places like damp basements. Better yet, find out where the water leaks are in your home and seal them. Seal up leaking pipes, and make sure that the bathrooms are well ventilated.

It would also be worth your while to investigate any exterior cracks that could be in your home. Set aside the money for caulk and seal those cracks as soon as possible. Also check your gutters and your downspouts so that water can properly drain.

Other than wood-based substances, silverfish have a sweet tooth. They love sugar, carbohydrates, and starches. You might have discovered this one by pouring yourself a bowl of Captain Crunch and a particularly silver crunchberry ran away.

Food that you can’t afford to throw away should be sealed up. There are plenty of containers on the market intended to replace the stock cardboard packaging. Silverfish can fit most places but they can’t fit through the seal of an airtight food container.

Taking the time to clear clutter from your home is also another step towards getting rid of silverfish. Clutter often consists of old newspapers, books, and magazines. So if you have a tick for saving every piece of paper that has something printed on it, you might be amassing the biggest meal a silverfish has ever seen.

We understand it’s difficult to get rid of reading material if you’re a bookworm, so take the stuff that you can’t bear to part with and put them in airtight containers, especially if the papers are kept in places where there’s comfortable, damp temperatures such as the basement and the attic.

Better yet, if you can bring yourself to get rid of stuff that you haven’t looked at in over a year, do so. Electronic reading material is more available and more affordable than it’s ever been before. Eliminate the paper, eliminate the silverfish’s food source.

Diatomaceous Earth, or simply DE, is a wonderful pest control method for silverfish. Diatomaceous Earth is a chalky, white powder consisting of the fossilized remains of a sort of algae called diatoms. When you’re small enough, those fossilized diatoms are like razor blades.

When silverfish come in contact with Diatomaceous Earth, it has a dual effect of dehydrating and cutting, so they’re basically cut up and dried into silverfish jerky.

You want to sprinkle it around the places where they like to hide, such as around the baseboards in your home and other places you might have spotted them. DE gets such a high recommendation because it doesn’t harm pets or people.

They aren’t meant to take care of your infestation problem by themselves, but you can speed up the effectiveness of other strategies by using silverfish traps. Yes, these things exist. Boric acid is the key ingredient in killing the silverfish once they’re trapped.

You will want to hide them in places where you’re bound to run into silverfish, like under the sink, and in the basement and attic. Don’t forget that boric acid can be toxic if ingested, so keep the traps where pets and children aren’t going to get into them and especially keep them away from your food storage.

Of course you don’t have to buy these traps in order to get boric acid by itself. Boric acid is a naturally toxic substance. Just as when using the traps, identify the places where the silverfish are congregating and sprinkle the boric acid in those places. Once the silverfish eat it, they will take it back to the family and then they will die.

A diluted potion of water and boric acid will make a powerful weapon as a spray. Just be sure to water it down, and do your best not to breathe any of the boric acid in. It isn’t gentle on the lungs. But as far as homemade remedies go, boric acid is among the best for cost and effect.

Boric acid carries the bonus of not only killing the silverfish, but also helps towards killing their eggs.

Wouldn’t it be nice if you had an insecticide that was both pleasant smelling and hard on silverfish? That’s exactly what cedar oil is. You don’t have to spend a lot to get this powerful repellent. Just buy cedar shavings and scatter them where you know that silverfish are hanging out.

Be advised that cedar shavings are also messy. So don’t put them anywhere in your home where you don’t mind a little bit of mess. Change out the shavings every week for maximum effect.

Another method you can go for is to mix cedar oil with water and spray this concoction into all the nooks and crannies that could be harboring silverfish. They won’t appreciate it, as the solution will reach into places you can’t. 

Another pleasant smelling remedy is cinnamon. Silverfish find the aroma, and the smell might help you relax while you’re dealing with your pest problem. So stock up on the cinnamon sticks and install them in places where they’re going to inconvenience your unwanted guests.

Believe it or not, citrus fruits act as an excellent and effective home remedy for silverfish. It’s the acidic nature of the aroma. But you don’t want to compound your silverfish problem with a gnat problem by having fruit everywhere getting rotten. Instead, take the peelings of lemons and oranges and place them where silverfish are likely to be lurking.

Lemon juice mixed with water and loaded into a spray bottle is a machine gun from the perspective of a silverfish. The cost of the ingredients is also cause for celebration. Just be diligent about getting the mixture into all the myriad places that silverfish hide during the day.

Naphthalene balls can be used for specifically protecting your clothes. Their odor is supposed to be intolerable to pests and drives them away. You can place them in your closet, wardrobe bookstore, and even suitcases and packing bags. You can place three to four naphthalene balls in humid and dark areas where infestations are common, including crevices in baseboards.

You don’t have to get fancy in order to get rid of silverfish. Ordinary table salt will serve the purpose of getting rid of them as well.

Silverfish find certain edibles irresistible, including the ones that are bad for them in large amounts. They silverfish will gorge on the salt and die from dehydration. Where necessary, Epsom salts can be substituted with no problem and be just as potent.

The only drawback is the length of time it could take to get rid of the pests entirely. It works, it just works slowly. It’s not RAID or depleted uranium. It’s salt. Give it time to work and be consistent about putting out fresh salt wherever there’s moisture and humidity.

Final Words

If you’ve recoiled in terror at the side of silverfish up until reading this, then we hope that this article brings you a little bit of relief. It’s always nice to find out that some terrible looking creature isn’t as terrible as you think.

Neither does that mean that you should allow these pests to set up camp in your home. They are going to be very difficult to get rid of if you try to do it by yourself, so the best thing you can do is set aside the money for a professional exterminator.

But should you run across silverfish in the outdoors, know that they are serving an important purpose by keeping our earth clean of decaying and dead material, nourishing the soil so that it will continue to sustain life on this planet.

Steve Foster

Mad about bugs and wanting to publish as many articles as I can to help educate people about these amazing beautiful creatures! For more info check out my about page

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