Pest guide

Silverfish

Silverfish are primitive, wingless insects that have been around for 400 million years. They love dark, humid spaces and eat starch — paper, glue, wallpaper paste, cereals, and natural fibers. They don't bite or transmit disease, but they damage books, photos, and pantry items.

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01 — Identification

What silverfish look like

Size

1/2"–3/4" long.

Color

Silvery-gray with a metallic sheen.

Shape

Carrot-shaped; three long tail filaments; two long antennae.

How to tell them apart

Fish-like wriggling motion when running.
Often confused with firebrats (browner, prefer hotter conditions).

02 — Life cycle

How they grow and reproduce

Slow-developing — 3 months to 3 years from egg to adult depending on conditions. Adults can live 8 years.

1
Egg
2 weeks to 2 months
Laid in cracks; needs humidity to hatch.
2
Nymph
3 months to 3 years
Resembles a small adult; molts 4–5 times.
3
Adult
2–8 years
Continues to molt throughout life — unusual for insects.

03 — Risks & behavior

What to watch for

Health risks

Do not bite, sting, or transmit disease.
Shed scales and droppings can aggravate allergies.

Home & property risks

Damage to books, wallpaper, photographs, and cardboard.
Holes in linen, silk, and rayon.
Contaminated cereals, flour, and dry pet food.

Behavior at a glance

Diet

Carbohydrates and starches — paper, glue, fabric sizing, grains.

When active

Nocturnal; hide in cool, humid voids during the day.

Peak season

Year-round indoors; populations build in humid summers.

Need humidity above 75% to thrive — dehumidifiers are highly effective.
Slow to reproduce, so populations build over months rather than weeks.

04 — Treatment

How to get rid of silverfish

Reduce humidity, treat harborages with desiccant dust, and remove paper clutter.

1
Run a dehumidifier in basements and bathrooms to bring humidity below 50%.
2
Apply diatomaceous-earth dust along baseboards, under sinks, and in attic eaves.
3
Place sticky traps to monitor activity and identify hot spots.
4
Store paper goods and dry food in sealed plastic bins.