Silverfish

Lepisma saccharina

Size12–19 mm

Active Season:Active year-round indoors. No seasonal variation as they require stable indoor conditions. More visible when humidity is high.

A primitive, wingless insect covered in metallic silver scales. Thrives in humid environments and feeds on starchy materials including paper, books, and wallpaper paste.

Anatomy

Anatomical Details

Identification

ColourSilvery-grey metallic sheen from overlapping scales that rub off easily

Size12–19 mm

Distinguishing Features

Carrot-shaped (tapered) flattened body
Three long, bristle-like appendages at the rear (two cerci and one central filament)
Two long antennae at the front
Fish-like wiggling movement with sudden stops
Completely wingless

Biology

Lifecycle

No metamorphosis (ametabolous) - nymphs hatch as miniature adults. Remarkably long-lived for an insect: 2-8 years. Continues molting throughout life, shedding skin up to 50 times.

Diet

Carbohydrate scavengers with a preference for polysaccharides. Feeds on starch, glue, book bindings, photos, wallpaper paste, sugar, hair, and dandruff. Can survive over a year without food if water is available.

Nesting

Strictly indoor pests in Canada - cannot survive winter outdoors. Prefer dark, humid environments with temperatures between 21-27C. Found in cracks, crevices, and behind baseboards.

Signs of Infestation

Live silverfish sightings

Often found trapped in bathtubs, sinks, or scurrying across floors at night. Their quick, darting movement is distinctive.

Feeding damage to paper

Irregular holes and surface grazing on books, documents, and wallpaper. Look for yellowish staining around damaged areas.

Shed skins

Tiny, papery molted exoskeletons found in hidden areas. Silverfish molt throughout their lives.

Yellow stains and scales

Yellowish stains on fabric and paper, plus tiny silvery scales rubbed off their bodies.

Pepper-like feces

Small, pepper-like droppings in areas of activity, especially in bookcases and storage areas.

Where They Nest

Bathrooms, especially under sinks and around tubs
Basements and crawlspaces with moisture issues
Kitchens near dishwashers and under refrigerators
Bookcases, filing cabinets, and storage boxes
Behind baseboards and in wall voids

Common Nesting Sites

Nesting Site Details

Distribution in Canada

Found in all provinces as an indoor pest. Cosmopolitan distribution worldwide. Cannot establish outdoor populations in Canada's climate.

Regional Prevalence

High

Moderate

Low

Rare/Absent

Active Season

Active year-round indoors. No seasonal variation as they require stable indoor conditions. More visible when humidity is high.

Prevention

Control humidity with dehumidifiers - keep below 50% relative humidity
Improve ventilation in bathrooms and basements
Fix plumbing leaks promptly
Store books and papers in sealed plastic containers
Reduce clutter in basements and storage areas
Seal cracks in baseboards and around pipes

Professional Treatment

Treatment focuses on identifying and addressing moisture sources that sustain populations. Targeted applications to cracks and harborage areas combined with humidity control provide long-term results.

Get General Pest Control Service

Scientific Classification