Silverfish (Lepisma saccharina) are small, wingless insects of the Thysanura order that get their name from their silvery-blue appearance and fishlike movements. They are also known as paramites, carpet sharks or fishmoths; sometimes they are confused with firebrats, another very similar insect of the Thysanusa order.
Silverfish are approximately one half inch to an inch in length. Their bodies are elongated and flattened with a tapered abdomen at the end, giving the appearance of a fish tail. Adult silverfish have a grayish hue and metallic shine (young are more whitish and lack the distinctive metallic shine). They can also be identified by the three sets of appendages (called cerci) on the sides of their body. The silverfish has two large antennae but lacks wings.
In nature, silverfish live in damp, warm places. They are frequently found in homes where there is warmth and humidity, especially laundry rooms, areas around ovens, heating units, fireplaces, hot water pipes, attics during the summer, and the furnace during winter. In apartments and homes, silverfish crawls along pipelines and through openings in walls or floors from one level to another. Sometimes they can be seen in the evening on the outside of doors or windows, or near porch lights, preferring these locations for their warmth. They are especially attracted to new constructions, where fresh lumber increases humidity and there is an abundance of freshly applied adhesive (caulk, wood glue, wallpaper, etc).
Silverfish are nocturnal, but you may see them during the day as well if the infestation is large enough.
Getting Rid of Silverfish
Silverfish are not dangerous to humans, but they can do a lot of damage to property due to their feeding habits. Silverfish feed on matter containing polysaccharides, especially starches and dexterin. These are especially prevalent in adhesives, such as glue and paste. Besides glue, these polysaccharides are commonly found in book bindings, paper, photos, sugar, coffee, hair, carpet, clothing and even human dandruff. They will also feed on tapestries, silk, linen, cotton, household dust and synthetic fibers. They have been known to consume dead insects and leather when other foods are scarce. They can be destructive if they get into areas with a lot of books or other items they commonly feed on.
Even if silverfish do not end up causing a lot of damage in the home, they are a nuisance simply by virtue of their presence. Their swarming about on windows, appearing in bathtubs and sinks and presence in the home in large numbers are undesirable.
Creature Control can take care of silverfish problems by applying a chemical pythrethrin to harborage areas and common entry points. Getting silverfish under control is a lengthy process, sometimes requiring several follow-up treatments over a 2 to 3 week period that need to be coupled with environmental modifications.
Environmental modifications are changes you can make around your home to discourage silverfish activity. Most important is to keep the house as dry as possible, especially basements, laundry areas, bathrooms and shower stalls. Frequent dusting will remove a food source of silverfish. Frequent cleaning out of cabinets, closets and storage areas is also important. Patch holes or spaces around pipes and conduits, and repair leaks and drips in plumbing. Using ventilation fans or dehumidifiers to suck up moisture is helpful in creating a drier environment less hospitable to silverfish. closed spaces can help discourage these pests. Keep collections of magazines, papers and books organized and occasionally rearrange them.