Silverfish in Calgary: Why They Show Up and How to Get Rid of Them
Quick answer: Silverfish do not bite people and do not spread disease, but they damage paper, cardboard, wallpaper, photos, glue and stored fabric, and they are a strong signal of damp air somewhere in the home. Lasting control is two parts: dry out the space, then treat the hidden cracks and voids where they live. If you are finding silverfish in the same room every week, a moisture problem is feeding them.
What silverfish are
Silverfish (Lepisma saccharinum) are small, wingless, silver-grey insects about 12 to 20 mm long with a tapered body, three tail bristles and two long antennae. They move in a fast, fish-like wiggle, avoid light, and are almost always seen at night or when a light switches on in a bathroom or laundry room. They can live for several years, and they feed on starchy material: paper, book bindings, wallpaper paste, cardboard, photos, cotton, linen, silk and grain products.
Do Calgary homes get silverfish?
Yes, and they are one of the most common indoor nuisance insects in the city. They are most frequent in:
- Bathrooms, laundry rooms, basements and crawl spaces
- Apartments and multi-unit buildings, where they move between suites through shared walls and service penetrations
- Older homes with damp foundation walls and unfinished basements
- Newer builds in the first year or two, while construction moisture is still drying out
- Kitchens with a slow drip under the sink or a poorly ventilated dishwasher
What they actually damage
Silverfish rarely cause a health problem, but the damage is real. Books, magazines, archives, photo albums and wallpaper are their favourite targets, along with cardboard storage boxes, cereal and pasta packaging, and clothing stored in damp closets. Their feeding leaves irregular holes, scraped surfaces and yellowish stains. For a home library, a home office or a rental with heritage wallpaper, that is enough reason to deal with them.
Signs of silverfish activity
- Live silverfish trapped in sinks, bathtubs or basins, where they cannot climb smooth sides
- Irregular holes or scraped patches on paper, book spines or wallpaper
- Yellowish stains or translucent shed skins near baseboards, shelves and behind appliances
- Small, dark, pepper-like droppings near stored paper or fabric
- Sightings at night when you turn on a bathroom or basement light
- Consistent humidity in the room: condensation on pipes and windows, or a musty smell
Moisture is the whole story
Silverfish need high humidity, generally above 75 percent, to thrive. In Calgary our summers are dry, but indoor moisture is a local problem, not a weather problem. Common sources:
- A dripping pipe, weeping valve or slow leak under a sink, toilet or washing machine
- Poor bathroom and laundry ventilation, or a fan that is undersized or clogged
- Condensation on cold water lines and basement walls in summer
- Unsealed tile and grout, and gaps around tubs, showers and vanities
- Downspouts, grading or foundation cracks letting water track along a basement wall
Bringing relative humidity down to about 50 to 55 percent in the affected rooms is the single most effective thing you can do. If you have a hygrometer, use it. If you do not, a simple one is inexpensive and settles the question.
How to get rid of silverfish
- Find and fix the water. Repair leaks, clear the fan, run the fan for 20 to 30 minutes after showers, and redirect downspouts away from the foundation.
- Lower the humidity. A dehumidifier in the basement or bathroom is worth it. Keep the target in the 50 to 55 percent range.
- Take away the food. Move photographs, documents and fabric out of damp rooms. Store paper, books and clothing in sealed plastic bins rather than cardboard boxes, and clear old cardboard and paper piles out of basements and closets.
- Clean the hiding places. Vacuum baseboards, floor cracks, behind appliances, under sinks, inside closets and along the bottom of shelving. Silverfish hide in tight, dark gaps.
- Seal the gaps. Caulk baseboards, trim, pipe penetrations, tile joints and shelf supports. Fewer cracks means fewer hiding places and less movement between rooms.
- Treat hidden voids where they breed. When silverfish keep returning, targeted crack-and-crevice treatment reaches the spaces your vacuum cannot: wall voids, cabinet interiors, plumbing penetrations and ceiling edges.
- In multi-unit buildings, coordinate. Treating one suite while silverfish keep moving from a neighbouring unit rarely ends the problem. Landlords and property managers should treat the shared structure and penetrate points, not just the reporting suite.
The steps that fall short on their own: sticky traps (they monitor, they do not control), repeated sprays on visible shelves, and drying agents sprinkled in areas that stay damp. Anything that does not address moisture is temporary.
Prevention checklist for Calgary homes
- Run bathroom and laundry fans every time, and keep the ducts and exterior vent flaps clear
- Fix drips immediately: under sinks, at valves, at the washing machine and around the water heater
- Dehumidify basements and crawl spaces through the summer
- Store paper, photos and off-season clothing in sealed plastic bins, in dry rooms
- Keep cardboard storage out of basements and garages
- Inspect and caulk baseboards, trim and tile joints annually
- Keep foundation drainage working: clear downspouts, keep grading away from the wall
When to call a professional
Call us when silverfish keep showing up after the moisture work is done, when they are spread across several rooms, when they are damaging books, documents or wallpaper, or when a multi-unit building keeps recycling the problem between suites. See our silverfish control page for how we handle it.
Pricing and booking
Silverfish pricing depends on the size of the affected area, whether the trouble is in wall voids and cabinets, and whether the building is multi-unit. Call (825) 760-5364 for an assessment and a clear quote, or check current service pricing on our pest control cost page. We serve Calgary, Airdrie, Cochrane, Chestermere, Okotoks and the surrounding communities.
Frequently asked questions
Do silverfish bite or carry disease? No. They are not a health risk. The reasons to treat them are property damage and what their presence says about moisture in the building.
Why do I find them in my bathtub? They fall in and cannot climb smooth vertical surfaces. Bathrooms are also the most humid room in the house, which is exactly what they want.
Will a dehumidifier alone get rid of them? It will stop them from thriving and will drive numbers down over time, but existing hiding places and nearby units can keep supplying them. Drying the space plus sealing gaps and treating voids is the reliable combination.
Do I need to throw out infested books and clothes? Usually not. Cleaning, drying and storing properly is enough. Discard items that are already mouldy, since mould points to a moisture problem that matters more than the silverfish.
How fast can we expect results? Most homes improve within two to three weeks after moisture is controlled and treatment is completed. Multi-unit buildings take longer because source units need to be included.
Related reading
- Spiders in Calgary: which ones bite and how to get rid of them
- Fleas in Calgary: getting rid of fleas in the home and on pets
- Boxelder bug control in Calgary
- Calgary pest activity calendar
Finding silverfish in the same bathroom or basement week after week? Call (825) 760-5364 or request a quote and we will trace the moisture first, then treat the hiding places they use.