Symptoms
- Small, wingless, silvery-gray insects that move in a fish-like wriggle
- Seen most often at night near the tub, sink, or baseboards
- Small holes or yellow staining on nearby paper or cardboard items
Likely causes
- CommonHigh humidity in the bathroomSilverfish need consistently damp conditions to thrive and reproduce.
- PossibleAccess to organic material like paper, cardboard, or fabric to feed onThey feed on starches found in paper, glue, and some fabrics.
- PossibleEntry from an adjoining damp space like a basement or crawl spaceThey can travel between areas of the house that share similar humidity conditions.
What to do
- Run the bathroom exhaust fan during and after showers to reduce humidity.
- Fix any leaks or persistent dampness around the sink, tub, or toilet.
- Remove or reduce paper, cardboard, and fabric clutter stored in or near the bathroom.
- Use a dehumidifier in the bathroom or nearby space if humidity stays high despite ventilation.
- Vacuum up any silverfish seen and clean the area to remove eggs, which are laid in cracks and crevices.
- Seal cracks around baseboards and pipe penetrations to reduce hiding spots and entry from adjoining spaces.
- Use sticky traps to monitor activity, and consider a pest control treatment if numbers stay high despite reducing moisture.
Tools and parts
- Vacuum
- Caulk gun
Silverfish sticky trapsSearch: “silverfish glue traps”
When to call a pro
Call a pest control professional if silverfish persist despite reducing humidity and sealing entry points.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.