Field plate · Lepisma saccharina
Silverfish
Silvery, tapering, wingless — a damp-paper pest older than the dinosaurs, at home in Erie basements and bathrooms.
Plate 17 of 28. Drawn in profile to the identification marks named below; the scale rule is a drawing convention — sizes are given in the text.
Identification marks
8–13 mm, carrot-shaped, covered in silver-grey scales, with two long antennae and three long tails at the rear. It runs in a darting, fish-like wiggle and shuns light.
Look-alikes it is confused with
Firebrats (mottled grey-brown, prefer heat near furnaces and boilers) and young silverfish, which are paler. Earwigs have obvious pincers and belong outdoors.
Where it hides in a house
Bathroom and basement baseboards, under sinks, behind stored boxes, and in the paper and book storage of damp lower rooms. It feeds at night on starch, glue, paper sizing, and dandruff.
Health & property risk, stated plainly
Property, in slow motion: surface grazing on book bindings, wallpaper, documents, photographs, and stored clothing — the kind of damage discovered when a box is opened after years.
What actually works
Dry the rooms (below about 50% relative humidity the population fades), store paper and books off basement floors in sealed bins, vacuum baseboards and shelves, and fix the plumbing drip that is running the nursery.
What doesn't
Treating a dry spare room while the wet basement that supplies the silverfish goes untouched, and mothballs, which are a labeled pesticide with real hazards — not a storage shortcut.
When to call a licensed pro
Call a pro when silverfish appear across several rooms or in a library, archive, or finished basement where the moisture source is not obvious.