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What are Silverfish?

Sheri Cyprus
Sheri Cyprus

Silverfish are the fishmoth species Lepisma saccharina. These eight-legged insects have scales on their bodies that allow them to move in a quick, curving manner that resembles that of a fish. They have a silver or gray coloring, but some also have a brownish cast. Most are between 0.5 inch (12.7 mm) to 1 inch (25.4mm) in length and they have very long antennae as well as three thread-like protuberances from their lower bodies. Silverfish live outdoors in damp, rocky or moldy areas, but easily thrive indoors in humid rooms such as bathrooms and are considered urban pests.

These insects were native to tropical climates before spreading to damp, cooler regions. Females lay up to 50 eggs at once, but only lay about 100 eggs during their lifespan. The lifespan of a silverfish is generally between two and eight years. They have soft bodies and are wingless. Silverfish can climb rougher surfaces, but not usually slippery surfaces and, as a result, they are sometimes found trapped in sinks and bathtubs.

A damp, rolled up newspaper can serve as a silverfish trap.
A damp, rolled up newspaper can serve as a silverfish trap.

In homes, silverfish tend to live behind baseboards around floors, or near plumbing and pipes in small cracks. Besides bathrooms, and sometimes kitchens or closets, silverfish can be found in crawlspaces and attics. Their eggs are often found in boxes of old clothing and books as silverfish eat the starch in fabrics and book paste. They are nocturnal insects and often prefer dark areas.

In homes, silverfish tend to live behind baseboards.
In homes, silverfish tend to live behind baseboards.

Vacuuming often, especially around baseboards, can help control the spread of silverfish in a home as it can eliminate the tiny eggs. Cracks and crevices around baseboards should be washed and dusted often to help reduce the population. Killing their eggs and removing their food sources are the best ways of controlling them.

Traps can also be put in areas where silverfish have been seen. A person create a trap by covering a small, open jar with masking or other fairly rough-textured tape. The insects will be able to climb into the jar, but not out again due to the slippery surface of the inner glass. A damp newspaper rolled up into a hollow shape may also serve as a silverfish trap.

Diatomaceous earth, a powder made up of crushed algae-like organisms called diatoms, is found in many pesticides, but is not harmful to the environment and is non-toxic to humans and pets. Homeowners can buy diatomaceous earth inexpensively in bags at garden centers and sprinkle it around baseboards where they have seen silverfish. People should wear a protective mask when working with the powder, as any dust-like substance can irritate the eyes and nose when it is not yet settled.

Frequently Asked Questions

What are silverfish and where can they be found?

Silverfish are small, wingless insects known for their silvery-gray color and fish-like movements. They are found worldwide, often in damp, dark areas like basements, attics, kitchens, and bathrooms. They thrive in environments with high humidity and can be found in both urban and rural settings, seeking out paper, glue, and textiles as food sources.

Are silverfish harmful to humans or pets?

While silverfish are not directly harmful to humans or pets, as they do not bite or carry diseases, they can cause damage to household items. They feed on carbohydrates, particularly sugars and starches, which means they can damage books, wallpaper, insulation, and clothing. However, they are more of a nuisance than a threat to health.

What do silverfish eat?

Silverfish have a varied diet that includes carbohydrates such as sugars and starches. They are particularly attracted to paper, glue, clothing, and pantry items like flour and oats. Their ability to digest cellulose makes them a common pest in homes, where they can damage books, wallpaper, and other paper products.

How can I prevent a silverfish infestation in my home?

Preventing a silverfish infestation involves reducing humidity and removing their food sources. Use dehumidifiers and ensure good ventilation in damp areas. Seal cracks and crevices to limit their access and keep dry foods in airtight containers. Regularly vacuuming and decluttering to remove potential food sources can also help keep silverfish at bay.

How long do silverfish live?

Silverfish are known for their relatively long lifespan compared to other insects. They can live for two to eight years, depending on environmental conditions. Their ability to survive for weeks without food and their rapid reproduction rate make them a persistent pest once they establish themselves in a suitable habitat.

Can silverfish cause an allergic reaction?

While silverfish are not known to cause allergic reactions through bites or stings, their presence can contribute to allergies in some individuals. Their molted skins and feces can become airborne and, when inhaled, may trigger respiratory allergies or asthma in sensitive people, similar to dust mites or other household allergens.

Discussion Comments


I hate these bugs. They are always in the library.


A couple of times I have seen this type of insect like creature which I think is either made of dust or has some type of interdimensional quality and is able to disappear since it could not possibly move at that many inches per nanosecond.


it is fantastic, but i want to know where they go in winter months when the temp. remains unsuitable for them. they live for 3 years on an average.

shafiq wani

kashmir university india

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    • A damp, rolled up newspaper can serve as a silverfish trap.
      By: by-studio
      A damp, rolled up newspaper can serve as a silverfish trap.
    • In homes, silverfish tend to live behind baseboards.
      By: Eugenio Marongiu
      In homes, silverfish tend to live behind baseboards.