Silverfish cannot fly. They belong to a group of primitive insects that are entirely wingless, lacking the anatomical structures necessary for flight. These ancient insects rely solely on their legs for movement. Confusion often arises because of their speed and the habitat they share with other, winged household pests.
The Definitive Answer: Silverfish Anatomy and Locomotion
Silverfish are classified under the order Zygentoma, meaning their ancestors never developed wings. They do not possess the thoracic structures required for flight muscles and wing attachment. Their bodies are flattened, elongated, and tapered, giving them a fish-like shape that contributes to their common name.
Their movement is a distinctive, rapid, and undulating motion that resembles a fish wiggling through water. They are agile runners and move quickly across surfaces, often scurrying for cover when disturbed by light. A silverfish has three long, tail-like appendages (cerci and a median caudal filament) that trail behind its abdomen. These structures, along with long antennae, are sensory organs that help them navigate their dark environment.
Common Confusion: Pests Often Mistaken for Flying Silverfish
The belief that silverfish can fly likely stems from misidentifying other small, similarly-shaped insects found in the home. A close relative, the firebrat, shares the wingless, tapered body shape and rapid movement of the silverfish. Both species are often confused with other small household pests that can fly, such as scuttle flies or plaster beetles, which may be seen flitting about near damp areas.
Clothes moths or pantry moths are small, winged insects sometimes found in the same dark, undisturbed areas. If a person sees a small, silvery insect flying in a basement or attic, it is likely one of these other winged pests, not a silverfish. Distinguishing characteristics, such as the presence of wings or the mottled brown color of a firebrat, help differentiate these look-alikes from the truly wingless silverfish.
Silverfish Biology and Preferred Environment
Silverfish are nocturnal scavengers that feed on materials high in carbohydrates and protein, making them a nuisance pest. Their diet includes starches like flour, sugar, paper, book bindings, wallpaper paste, and even some synthetic fabrics and glues. They feed by scraping off individual layers of starchy material, which results in characteristic thinning and ragged-edged holes in paper or fabric items.
These insects thrive in dark, quiet environments with high humidity, typically between 75 and 95 percent. Common habitats include basements, attics, crawl spaces, and bathrooms, as these areas provide the necessary moisture. Silverfish can survive without food for up to a year, but they require a source of moisture to prevent desiccation.
The life cycle of a silverfish is slow, as they undergo incomplete metamorphosis. They may take two to three years to reach maturity. Adults can live for two to eight years, molting continuously throughout their lifespan. Females lay small clutches of eggs in cracks and crevices, contributing to their persistent presence in undisturbed, damp areas.