We live on the fifth floor of an apartment building and recently found silverfish in our bathroom. Where did they come from? I’m worried that they are coming up through the building from ground level? If so, what should we do?

The silverfish could have initially come from any direction, or from any other apartment, or you could have accidentally carried them into your apartment from elsewhere. If you’re on the top floor, they could even have moved down from the attic or ceiling void space above.

Silverfish are not really exotic pests; they are very much like cockroaches in their habits. They hide during the day in cracks and crevices and move about quickly at night. Like cockroaches, silverfish are scavengers and feed on a variety of things, including fabrics, papers, and foods, but they are most attracted to starchy items.

Like cockroaches, silverfish can move throughout an apartment and can move from apartment to apartment. In homes with attics, silverfish often occupy the attic space where they get into cardboard boxes and feed on stored clothes, books, papers, and other items.

Have an Exterminator Inspect Your Apartment

The silverfish are likely in your bathroom because of the higher moisture level; it doesn’t necessarily mean that they are feeding there. It could, however, mean that there is a plumbing leak that is attracting the silverfish (see Silverfish Can Mean a Moisture Problem).

A professional exterminator can inspect your apartment to find the prime spots for silverfish (see Silverfish Infestations – Finding the “Hot Spots”). If you have lots of boxed items or stored fabrics or papers, those are the places to begin a silverfish inspection. Silverfish can also infest foods in your kitchen. Check packaged foods that are high in carbohydrates or protein such as flour, cereals, or dried meat.

How To Prevent Silverfish

Because silverfish act much like cockroaches, they can be controlled in much the same way. Control usually requires professional treatment of cracks and crevices where silverfish hide. When silverfish are infesting attics or wall or ceiling voids, granular baits or space treatments can sometimes be used. Hopefully, you can convince your property manager to have apartments on all sides of you (both sides, also above and below) inspected for silverfish to make sure they are not moving in from an infested apartment next door.

You should also make sure that you have a tight-fitting front door with a sweep underneath. To help keep silverfish out, caulk any openings between your apartment and apartments next door or common void spaces, such as around pipes under the kitchen sink, electrical outlets and wall switches, light fixtures, cable conduits, etc.

Photo: Christian Fischer [CC-BY-SA-3.0], via Wikimedia Commons

Sign up for our biweekly email newsletter for more information about bugs and pests!