What Are Silverfish
Silverfish can be identified by their white to brown-grey or bluish-silver color, as well as their teardrop-shape. These insects measure between 12-19 mm in length and have three long bristles at the back. They grow from egg to adult without any visible change in appearance.
They move very quickly, and seemingly ‘slither’ rather than crawl. They like dark places, and although they can survive in almost any climate, they like dark, damp places with high humidity levels. They can be found most often in bathrooms, basements, attics, and kitchens. They can also be found in stored boxes in sheds or garages.
They can be difficult to identify because they like to hide in cracks and crevices that are inaccessible to humans.
They feed primarily on starches and sugars, including:
- glue in books
- dead insects
- clothing such as silks or linens
- unopened food packages
- damp papers and newspapers
Part of the reason silverfish infestations can be difficult to eradicate is because they reproduce quickly. The amount of eggs the female lays can vary from species to species, from one a day to twenty a day.
Silverfish perform love dances prior to mating. First, they touch their antennae together. Next, the female flees. When they reunite, the male vibrates his tale and deposits packets of sperm called spermatophores which the females take into themselves via their ovipositors. Nymphs (eggs) develop faster in very humid environments, and this is part of the reason they like humid places so much.
Females lay several eggs each day, in cracks, crevices and dark places, which make them difficult to spot. They are also quite small, about 1 mm in length. When first laid, they are soft and white, but after a few hours, they harden and become a yellowish color. The eggs are barely visible to the human eye.
Once the eggs hatch, silverfish are white in color, although as they grow, they become silver-white or gray. Upon hatching, they are fully formed.
The life cycle of silverfish can range from three to four months from egg to adult. Eggs can hatch anywhere from 19 to 60 days after being deposited, depending upon humidity conditions. The more humid the area, the faster the eggs will hatch. They are known to thrive in almost any environment, but again prefer humid areas.
Young silverfish are simply miniature versions of adults. They molt several times until they reach adulthood, and continue to molt throughout their adult lives. In fact, they may experience up to 50 molts throughout their entire lifetime.
A silverfish can live up to two – three years.
Identifying an Infestation
It can be difficult to identify an infestation, as silverfish are generally quite secretive. It’s possible that an infestation may go unnoticed for a long period of time. They are nocturnal and shy away from light, dry spaces. Finding just one silverfish in a sink or box may be an indication of an infestation.
Once they find a suitable food supply, they will attempt to make their nest as close as possible to it.
Feeding damage can also be an indication of an infestation, as can their pepper-like feces.
Most homeowners realize they have an infestation when they start finding them in sinks or bathtubs.
Unfortunately, because an infestation can take a long period of time to notice, it allows their population to grow exponentially. They reproduce quickly and females lay eggs in clusters throughout the day.
An infestation left untreated can cause severe damage to your home and belongings, not to mention cause a feeling of nervousness and unrest (who wants to sleep knowing their house is infested with bugs!). Luckily, there are several effective ways to get rid of an infestation and keep them from coming back.
How to Repel Silverfish Naturally
There are several natural and organic ways to repel silverfish and help prevent an infestation from occurring. There are varying schools of thought on just how effective these are, and are generally not considered effective over the long term.
Cinnamon is one of the more popular methods of repelling silverfish, as they don’t like the smell. Simply place pure cinnamon sticks in places where they are most likely to show up, such as in cupboards under the kitchen sink, in closets, the laundry room, basement, and attic. If you don’t have cinnamon sticks, putting ground cinnamon in a small sachet will work as well, although not as effectively.
Lavender oil is also effective. Mix together one teaspoon of oil with one cup of water in a spray bottle. Spray around walls, carpets, floors in spaces where silverfish are prone to be. Be sure to spray on a regular basis so the smell stays fresh. While it can be applied to some fabrics, it shouldn’t be sprayed on delicate items, as it can cause irreparable damage.
Moth balls are another effective method of repelling silverfish. Place moth balls wherever they have been seen, including your fabrics, and old boxes.
Citrus sprays can be used as well, and these are available at most home improvement stores. They are specifically manufactured to repel and kill silverfish. Don’t use general cleaning solutions with citrus in them – they do not repel bugs and will be of no help.
Spices such as whole cloves, sage, and bay leaves will also deter them, as they don’t like the strong scents. Put spices in a sachet and place where you see silverfish.
Diatomaceous earth (food grade) is a white powder that will kill and dehydrate silverfish when they walk through it. Simply dust all areas where they can hide, including cracks and small holes. Although it’s lethal to silverfish and other pests, it is non-toxic for pets and humans.
Cucumbers are another effective repellent. Cut a cucumber into thick slices and place in areas where silverfish have been seen. Replace them once they dry up, or they will no longer be effective.
Cedar shavings can help repel them, by placing the shavings in cracks, holes and dark places that the bugs have been seen.
You may have to try a combination of these before you completely get rid of the infestation. It may take weeks or even months to get rid of them entirely. Once you have gotten rid of them, don’t stop using repellents on a regular basis. This will help keep them out of your home for good.
Remember too, that these are used to repel the insects, not kill them. If you find some in your home, you may need to use other methods to get rid of them, and then use the above suggestions to keep them at bay.
Other Methods of Exterminating Silverfish
Sometimes, the only effective method of killing silverfish and getting rid of an infestation is to call a professional. Keep in mind that most professionals will use toxic sprays and solutions to get rid of them. If you have pets in your home, make sure you communicate that, so extra precautions can be followed.
If you hire a professional, be prepared to pay a tidy sum. Research at least three companies and choose a reputable one that has been in operation for a few years. Watch out for outrageous claims – they cannot guarantee that silverfish will never come back, and they cannot guarantee that they will be gone with just one application.
An exterminator will be able to come into your home, assess the situation and recommend a solution that is best for you. A qualified professional should be able to explain the entire process to you, so that you can make an educated decision. Hiring a professional may be one of the quickest way to get rid of silverfish, but it won’t be the least expensive.
There are several baits and traps you can make or buy in order to get rid of silverfish. Using these may take longer to get rid of them all, but they are effective over time.
Moisten newspapers and tie them up with elastics. Leave them out overnight to attract and catch the silverfish. The next morning, you can either burn the papers with the bugs in them, or throw them in the trash. Keep doing this until no more bugs are caught in the papers.
Use a glass jar or container and cover the outside with masking tape. Put some bread in the jar and fill halfway with water, along with one teaspoon of sugar as bait. The bugs will climb up the tape and fall into the jar. They will die because they won’t be able to climb back up the slick sides to escape their prison.
Sticky traps are generally effective and are available at most home improvement stores. They are not expensive and are easy to set up.
Damp cotton or starchy food items can also be used as bait.
Boric acid can also be used, although this can be toxic so use with caution. It will kill hatching nymphs, as well as adult silverfish. Sprinkle the powder around the infestation, and reapply once the powder gets damp.
Liquid pyrethrin is effective in killing adult silverfish, but not the eggs. Spray the liquid into cracks and around doors and windows.
Again, you may have to try a combination of these methods before finding one that is most effective. Once you’ve gotten rid of the infestation, use some of the repelling methods to make sure they stay away.
Tips for Keeping Silverfish out of Your Home
Since silverfish like damp, humid places (75 – 95%), it’s a good idea to ensure the humidity in your homes stays around 50%. Fans and dehumidifiers will help you achieve this. Fix all leaks, minimize available and standing water, and ventilate closed rooms and attics.
Caulk all crevices, cracks and small holes in your home and garage to keep them from using them as an entrance-way.
Clean and inspect all possessions in your home, including old boxes, old papers, book shelves, cupboards and wardrobes. Check for signs of silverfish, either from the pepper-like feces or damage to your items.
All food sources should be placed in air-tight containers.
Mop, dust and vacuum often to get rid of eggs.
Repair or remove old wallpaper.
Remember that sanitation goes a long way towards keeping your home infestation-free.
Go through old boxes and items – if you don’t need them anymore, throw them away, or have a garage sale.
Silverfish feed on a variety of foods, so keeping potential food sources away from openings, and humid spaces will help to keep them out of your home.
Are Silverfish Dangerous?
Silverfish are not considered dangerous, and are not known to bite humans. They are more of a nuisance than they are a danger to humans or pets. If they go unnoticed for a long period of time, they can cause mass destruction to possessions and homes, and could cause homeowners hundreds or even thousands of dollars for repairs.
They are not known to carry diseases and will flee to safety when disturbed. They move very quickly and only forage for food at night. They can go a long time without food.
That doesn’t mean of course, that you shouldn’t be on the lookout for them. When you do spot them, it’s extremely important to get rid of them as soon as possible.
Do Silverfish Eat Clothes?
Silverfish are especially attracted to damp clothing and will feed on fabrics such as cotton, silk and linen. Over time, these clothes will become destroyed and no longer wearable. That’s why it’s so important to identify an infestation early on and deal with it as soon as possible.
While silverfish are creepy and somewhat difficult to eradicate, they are not venomous and do not bite. Even so, getting rid of them as soon as they are identified should be a priority. There are many effective ways to get rid of them, and to repel them from coming back again. Several methods may be necessary before getting rid of them entirely.