Silverfish are small, wingless insects that many people encounter in their homes. These insects are silver or pearl-gray in color and have a unique, fish-like appearance due to their slim, tapering bodies and overlapping scales source. You may wonder how long these pests typically live.
The lifespan of silverfish varies but can range from two to eight years, depending on factors such as species and environmental conditions source. A female silverfish has the potential to lay over 100 eggs during her lifetime, with the eggs hatching in three to six weeks source. It’s important to understand their lifecycle and habits in order to effectively manage an infestation.
Silverfish Life Cycle
- Silverfish females lay over 100 eggs during their lifespan.
- They lay eggs singly or in small clusters in cracks and crevices.
- The eggs are about 1/25 of an inch long and hatch in three to six weeks.
- Nymphs look like small whitish adults and are about 1/20 inch in size.
- They take on the adult color in four to six weeks.
- Silverfish adults have a lifespan of 2-8 years.
- They continuously molt throughout their lives.
- Adult body length is typically 0.85 cm (0.33 in) with two long antennae.
Comparison of Egg and Nymph Stages
|Egg||1/25 inch||Laid singly or in clusters||Hatch in 3-6 weeks|
|Nymph||1/20 inch||Small, whitish, adult-like||Adult color in 4-6 weeks|
Understanding Silverfish Habitat
Silverfish prefer dark and damp areas inside homes. They are often found in:
These insects require high humidity, typically above 75%, to thrive. For example, they are drawn to moist environments like leaky pipes or damp basements. In the home, silverfish can infest books, paper materials, and even damage silk and synthetic fabrics1.
Outside, silverfish inhabit areas with moisture and protection, such as:
- Under rocks
- In leaf litter
- In tree bark crevices
While they can survive outdoors, silverfish also easily find their way into buildings through cracks or openings around windows and doors2.
Here’s a comparison table of silverfish habitats:
|Indoor||Dark, damp||Basements, attics|
|Outdoor||Moist, protected||Under rocks|
Understanding and recognizing these habitats can help in addressing and preventing silverfish infestations in homes and other buildings.
Preventing and Controlling Silverfish Infestations
Dehumidify your Home
Silverfish thrive in moist environments, so one way to prevent infestations is to reduce the humidity levels in your home. Use a dehumidifier to help control moisture and ensure proper ventilation, especially in areas where humidity levels are higher (e.g., bathrooms and basements).
Seal Cracks and Crevices
These pests often enter homes through small openings around the foundation, walls, and windows. To stop them from accessing your living space:
- Seal any visible cracks or crevices
- Install weather-stripping around windows and doors
- Repair any damaged screens
Clean and Vacuum Regularly
Silverfish and other pests are attracted to food debris and dust, so it’s essential to maintain a clean environment. Vacuum your home regularly, focusing on areas where pests might hide, such as behind furniture and appliances. Additionally, frequently clean and dust your home to minimize the materials that attract silverfish.
Store Food Properly
Since silverfish are drawn to food sources like flour, sugar, and starches, storing food in sealed containers can help prevent an infestation. Use airtight containers to keep food secure and minimize any food waste and spills.
Natural and Chemical Pest Control Methods
There are several ways to control and eliminate silverfish infestations. Two common methods include:
- Diatomaceous earth (DE): A natural, non-toxic powder that can be used to kill pests by damaging their exoskeleton. Sprinkle DE around areas where silverfish are present.
- Boric acid: A chemical compound that acts as a poison for silverfish. Use boric acid in small amounts around infested areas, but keep in mind that it can be toxic to pets and humans if ingested.
Additionally, other options, such as essential oils and pest traps, can help in controlling silverfish populations. If infestations become severe, contact a professional pest control service to address the issue.
|Diatomaceous earth||– Natural
|– May be less effective compared to chemicals|
|Boric acid||– Effective in killing silverfish||– Toxic to pets and humans, if ingested|
Remember, keeping your home clean and free of moisture is critical in preventing and controlling silverfish infestations. Using a combination of proper hygiene, preventive measures, and pest control methods will help keep these pests at bay.
The Damage Silverfish Cause
To Books and Paper
Silverfish are attracted to items high in carbohydrates, like the glue found in book bindings and wallpaper. Their diet consists of paper materials, often causing damage to:
- Cardboard boxes
For instance, they may eat the glue from book spines, causing pages to loosen and fall out.
To Clothing, Linen, and Carpets
Silverfish can also damage items like clothing, linen, and carpets. They are particularly attracted to items made of:
You may find their small, oval-shaped scales around damaged materials. For example, a cotton shirt may have holes after a silverfish infestation.
To Food Items
They are known for invading food items, such as:
- Pet food
In a kitchen, you may discover silverfish hiding in crevices or near baseboards, seeking carbohydrates.
|Material||Impact of Silverfish|
|Books and Paper||Damage to bindings, loose pages|
|Clothing, Linen, and Carpets||Holes, tears, loose fibers|
|Food Items||Contamination, consumption|
Their presence can cause damage to belongings and food items, so it’s important to take preventive measures to avoid silverfish infestations.
The Biology and Behaviour of Silverfish
Silverfish are small, wingless insects that are silver or pearl-gray in color. Their bodies are covered in tiny glistening scales, giving them a fish-like appearance. They typically measure around 0.85 cm (0.33 in) in length and have two long antennae1.
These household pests primarily feed on cellulose and polysaccharides found in various materials. Their diet includes:
- Paper and cardboard
- Coffee grounds
Silverfish are nocturnal creatures, meaning they are most active during the night. This behavior helps them avoid predators such as spiders, centipedes, and certain types of insects. Like cockroaches, silverfish are also attracted to moist and damp environments, making them common indoor pests.
Comparison between Silverfish and Firebrats:
|Appearance||Silver or pearl-gray with tiny glistening scales||Similar but brownish|
|Size||0.85 cm (0.33 in)||Similar|
|Diet||Cellulose, polysaccharides, coffee, dandruff, plaster||Similar|
|Habitat||Indoor, damp environments||Similar but prefer warmer areas3|
|Nymph stages||Multiple molts over 2 years4||Similar|
Pros and Cons of Silverfish Control Methods
- Pyrethrin insecticides:
- Effective in controlling silverfish
- Relatively low toxicity to humans and pets
- May require multiple treatments
- Some silverfish and other pests can develop resistance
Additional Facts and Considerations
Silverfish and Allergens
- Silverfish may trigger allergies in some individuals
- They shed scales that can contaminate surfaces
Silverfish are known for their fish-like appearance and are covered in tiny glistening scales. They shed these scales throughout their lifetime, which can contaminate surfaces in your home. For sensitive individuals, these scales can trigger allergies with symptoms such as sneezing, itching, or watery eyes.
Bites and Other Potential Health Risks
- Silverfish do not bite humans
- They may indirectly introduce health risks through contaminating food or belongings
Although silverfish do not bite humans or directly harm us, they can still pose indirect health risks. For example, they may feed on items such as rolled oats, dried meat, and other protein sources, potentially contaminating your food. Additionally, they may damage materials such as books, wallpapers, and textiles.
Commonly Confused Insects
- Firebrats are similar to silverfish but prefer warmer environments
- Silverfish and firebrats may be mistaken for each other due to their similar appearance
Silverfish are sometimes confused with firebrats, another type of bristletail insect. They have similar physical traits—such as being flattened and elongate, with long antennae and tail-like appendages at the end of the abdomen—however, they differ in their preferred living conditions. Firebrats tend to thrive in warmer environments, whereas silverfish often reside in locations with higher humidity, such as bathroom sinks or bathtubs.
Comparison of Silverfish and Firebrats
|Appearance||Flat, elongate, glistening||Similar to silverfish|
|Habitat||Bathroom sinks, bathtubs||Warmer environments|
By understanding these common misconceptions, you can better identify silverfish in your home and mitigate any potential health risks they might pose.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Silverfish
Subject: What is this bug?! Are they harmless?!?! Please help!
Location: Windsor, ON Canada
July 23, 2015 2:17 am
Hi there! I’m from Windsor, ON Canada and for a while now I have been seeing these small bugs coming in and out from underneith the moldings of my bathroom wall. I never see them during the day but I work midnights so when I get home and I open the light to the bathroom there it is! It sees the light and scurries back into the cracks. The house is only 3 years old and I’m thinking they’re just visiting from outside because the only place I see them coming from is the one bathroom wall that faces the outside. Haven’t come across them elsewhere in the house. What are these bugs? They’re very small and you can’t even tell they have legs unless you look very close so they just look like a very fast baby worm wiggling away. You can get a better look at the colours and shape of it from the photo I will provide. Thanks!
This is a primitive insect known as a Silverfish, and they are common household pests. According to BugGuide: “often found indoors in damp environments; the Common Silverfish is frequently seen in bathrooms and kitchens, whereas the Firebrat is usually found in basements around furnaces and in insulation around hot water and heating pipes; these and other species also occur outdoors under bark, in leaf litter, caves, ant nests, deserts, etc.” They have plenty to eat indoors. According to BugGuide, they are: “omnivorous: starchy foods, cereals, moist wheat flour, glue on book bindings and wallpaper, starch in clothing made of cotton or rayon fabric.”
Letter 2 – Silverfish
Location: Thousand oaks
August 11, 2016 12:41 am
I have been seeing this bug everywhere in my room and idk what it is
Signature: Nikki Rivera
This is a Silverfish, a common household pest.
Letter 3 – Silverfish
Subject: strange bug
November 29, 2016 3:13 pm
Wondering whats this guy, recently moved some things out of a self Storage building and found them in my belongings.
Signature: Justin s
There is not much left of this Silverfish, a common household pest that will eat most anything organic, including the glue in book bindings.