How do silverfish get in the house?

Updated November 21, 2016

Silverfish enter houses on timber, plasterboard, infested cardboard boxes, old books and furniture. They can also come in from nearby woodland or meadows.


Silverfish are an annoyance, but not a health threat. They don't carry disease and, because they have weak jaws, they don't do much damage. They like to eat starches and proteins and will eat grain products, dried meats and the glue behind wallpaper or in bookbindings. Although large infestations are possible, they are rare. When they do happen, the silverfish may damage leather, fur, silk and rayon; contaminate food; stain clothing and damage curtains.


Silverfish are primitive insects that grow to be about 1.25 cm (1/2 inch) long. The insects are shiny and silver or pearl-grey in colour. It is wingless, with a soft body, long, slender antennae and three tail-like protrusions from the end of the abdomen. They run very fast and are most active at night.


Silverfish prefer damp, cool places and can be found in cellars, cupboards and bookcases. They are also found behind skirting boards, under vinyl floors and carpet and lurking around window frames.

Controlling infestations

If only a few silverfish are present, you may not need to do anything. However, if you have an infestation, it's better to try non-chemical approaches first. Silverfish need a lot of moisture, so the first step is to eliminate dampness. Fix leaky plumbing and use a dehumidifier. Keep areas such as the bathroom, utility room and basement clean and dry. Next, seal all cracks and crevices to eliminate breeding and hiding places. Patch holes around pipes and caulk cracks around windows and doors. Finally, remove food supplies by storing paper, books, food and clothing in tightly sealed cabinets or containers. Because household dust is a food source, vacuuming and dusting will also help. Keep new silverfish out of the house by inspecting items brought into the house, especially if they've been in storage.

Chemical control

Only use a pesticide if you have a large infestation that can't be controlled without chemicals. A pesticide should be used along with the methods outlined above, not by itself. Be sure to read and follow directions on the pesticide label carefully. If properly applied, an insecticide should show results in two or three weeks. A continued problem means undiscovered hiding places. If professional help is needed, contact a licensed, reputable pest control company.

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About the Author

Lani Thompson began writing in 1987 as a journalist for the "Pequawket Valley News." In 1993 she became managing editor of the "Independent Observer" in East Stoneham, Maine. Thompson also developed and produced the "Clan Thompson Celiac Pocketguides" for people with celiac disease. She attended the University of New Hampshire.