Not typically a household pest
Silverfish
Lepisma saccharina
A wingless, teardrop-shaped insect up to about 3/4 inch long, covered in silvery-grey scales, with three long bristles at the rear. It feeds on starches — paper, glue, wallpaper paste, and stored goods — and moves with a distinctive wiggling “swim.”
Visible identification features
- Body 1/2–3/4 in (12–19 mm), tapering from wide head to pointed rear
- Silvery-grey, uniformly scaled; no wings at any stage
- Three long tail bristles (cerci) as long as or longer than the rear legs
- Antennae nearly as long as the body
- Nocturnal; darts for cover when a light comes on
Why it may be in your home
Silverfish need humidity and starch. They gather in bathrooms, attics, basements, and around bookshelves, wallpaper, cardboard boxes, and stored cereals. Damage shows as irregular scraping marks and yellowish stains on paper and book bindings.
Lookalikes
- House centipede
Centipedes have a segmented body with many long, banded legs; silverfish have six short legs, no wings, and three tail bristles.
- Firebrat
Firebrats share the same teardrop shape but are grey-brown and mottled, and favor hot spots near furnaces, ovens, and water heaters.
Confused with something else?
Next steps
- Lower humidity: dehumidify damp rooms, fix drips, and ventilate the bathroom and attic.
- Store paper goods, books, and starch-based foods in sealed containers rather than cardboard.
- Vacuum cracks and crevices to remove eggs and food debris; discard the vacuum bag outside.
- Reduce harborage: caulk baseboard gaps and keep stacks of paper off floors.
Sources
- Silverfish and Firebrats — University of Kentucky Entomology
- Silverfish and Firebrats — University of Minnesota Extension
Updated 2026-09-03. Claims are limited to these sources.