What Are Silverfish and Why Are They in My House?
If you've ever seen a small, fast-moving, silver-coloured insect dart across your bathroom floor, chances are you've encountered a common silverfish. These tiny, ancient bugs are a common nuisance in homes in many places around the world and they tend to appear when you least expect them. But what are silverfish exactly? Why are they in your home? And more importantly, how can you get rid of them?
We'll help you understand everything you need to know about silverfish, including their behaviour, where they hide, and why your home might be the perfect environment for them.
What Are Silverfish?
Silverfish are small, wingless insects named for their shiny, silvery-grey colour and fish-like movements. They’re part of a group of primitive insects that have existed for over 400 million years.
- Scientific name: Lepisma saccharina
- Size: 12–19 mm (about half an inch)
- Colour: Silvery or metallic grey
- Body shape: Tapered, fish-like appearance
- Movement: Quick and wriggly
Although silverfish may look creepy, they are not dangerous to humans. They don’t bite, sting, or spread disease. But they can cause damage to your belongings especially books, clothing, wallpaper, and dry food.
Why Are Silverfish in My House?
Silverfish love dark, damp, and undisturbed areas. They thrive in places with high humidity (above 75%) and prefer temperatures between 21°C and 27°C. Your home, especially if it has warm, moist spaces, can be the ideal place for them to settle in.
Common reasons silverfish enter your house include:
- Seeking moisture (e.g., bathrooms, kitchens, laundry rooms)
- Attracted to paper, cardboard, glue, or starchy food
- Cracks, gaps, and poorly sealed windows or doors
- Stored boxes, books, and clutter in dark spaces
Silverfish often enter through cracks in the foundation, open vents, or when you bring in cardboard boxes or secondhand furniture.
Where Silverfish Hide
You may not see silverfish during the day as they’re nocturnal and avoid light. But they’re often found in:
- Under bathroom sinks
- Behind baseboards
- Inside closets and cupboards
- In attics or basements
- Behind wallpaper or loose tiles
They tend to hang out where they have easy access to moisture and food, so areas near leaky pipes or high humidity zones are their favourite spots.
What Do Silverfish Eat?
Silverfish feed on starches, sugars, and protein. They often eat:
- Book bindings and paper
- Glue and wallpaper paste
- Flour, oats, and cereals
- Clothing and fabrics (especially cotton and linen)
They don’t need to eat often, but they can survive well over several months without food making them tricky pests to get rid of without proper control.
Are Silverfish Harmful?
Silverfish are mostly a nuisance. They aren’t harmful to your health, but they can cause damage to household items over time. Here’s what they can do:
- Leave small holes in paper or fabrics
- Leave yellow stains or shed skins behind
- Contaminate food in unsealed containers
Large infestations can be frustrating to deal with, especially when they begin damaging items that are hard to replace like vintage books or important documents.
How Do You Know If You Have Silverfish?
Signs of a silverfish infestation include:
- Seeing live silverfish, especially at night
- Tiny pepper-like droppings
- Yellow stains or tiny scrape marks on paper or fabric
- Finding shed exoskeletons in corners or drawers
It may take time to notice them, but once you do, it’s important to act quickly before the infestation spreads.
How Do Silverfish Multiply?
Silverfish reproduce slowly, but their populations can grow over time if left unchecked.
- They lay eggs in cracks and crevices
- Each female can lay up to 100 eggs in her lifetime
- Eggs hatch in 3–6 weeks
- Juveniles look like mini versions of adults
Given the right conditions, silverfish can live up to 3 years! So a few insects can turn into many without you realizing it.
Silverfish are strange, ancient insects that can become frustrating household pests. They thrive in dark, moist places, feeding on everyday items like paper, glue, and food crumbs. While they don’t pose any direct threat to your health, they can damage personal belongings and quickly become an ongoing nuisance.
Now that you know what silverfish are and why they’ve taken up residence in your home, you're one step closer to getting rid of them for good. Check out our other blog posts, and we’ll explore natural remedies to get rid of silverfish, as well as homemade silverfish traps, and expert strategies to eliminate silverfish and prevent them from coming back.
Say goodbye to silverfish for good!