How to identify and get rid of Silverfish

Ancient survivors of over 400 million years, silverfish are among the oldest insects on Earth. Fossil records show these wingless pests have existed since some of the first land-living animals. They have two long antennae and a smooth, silvery body. They move with quick, side-to-side motions, similar to a swimming fish, which explains their name. Despite their short and thick legs, silverfish can move at surprising speeds, making them difficult to catch.

Silverfish have thrived for millions of years due to their ability to adapt to harsh environments. However, they are best known for their destructive feeding habits, targeting books, photographs, wallpaper, clothing, and dry food supplies. Although silverfish do not breed as rapidly as some pests, their long lifespan (up to six years) allows infestations to grow substantially over time. If left untreated, they can spread to multiple home areas, leading to widespread damage. Monitoring, controlling, and eliminating factors that attract them is essential to prevent silverfish infestations.

What are silverfish?

Silverfish (Lepisma saccharina) are small, wingless insects known for their silvery-grey scales and wiggling movement. Their elongated, carrot-shaped bodies taper at the rear, and they measure between 12–19mm in length. A distinguishing feature of silverfish is their three bristle-like appendages extending from their tail. Their rapid, side-to-side motion resembles that of a swimming fish, giving them their name.

Evolutionary history

As one of the oldest surviving insect species, silverfish have existed for over 400 million years, predating dinosaurs. Their ancient lineage and minimal evolutionary changes testify to their adaptability and resilience in various environments. 

Habitat and behaviour

Silverfish are nocturnal pests that thrive in dark, humid, and undisturbed environments. During the day, they hide in cracks, behind bookshelves, inside storage boxes, and under sinks. At night, they emerge to feed on starch-based materials, including paper, glue, fabric, and food crumbs.

Due to their fast movements and nocturnal nature, silverfish often go unnoticed until an infestation becomes severe. Their ability to survive in diverse conditions makes them a persistent household pest, particularly in homes with high humidity and abundant food sources.

What attracts silverfish to your home?

Silverfish invade homes in search of food, shelter, and moisture. Several factors increase the likelihood of an infestation:

1. High humidity

• Silverfish require humidity levels of 75% or higher to survive.
• They are commonly found in bathrooms, basements, kitchens, and laundry rooms, where moisture levels tend to be high.
• Leaky pipes, poor ventilation, and condensation create the perfect breeding environment for these pests.

2. Starchy food sources

• Silverfish feed on materials that contain carbohydrates and polysaccharides, including:
• Books, magazines, and paper products (they eat the glue in book bindings).
• Wallpaper paste and adhesives (they chew on the glue behind wallpaper).
• Fabrics and clothing (especially those made from cotton, silk, and linen).
• Stored dry goods such as flour, pasta, cereal, and oats.

3. Dark and undisturbed areas

• Silverfish prefer hiding in dark, cluttered spaces such as attics, basements, storage boxes, and old furniture.
• They often go unnoticed for long periods because they avoid light and human activity.

4. Warm temperatures

• Silverfish thrive in temperatures between 22-30°C.
• They are most active in spring and summer, but indoor heating can keep them active year-round.

Signs of a silverfish infestation

Having a silverfish infestation can be a pain. Silverfish are experts at hiding and are often difficult to detect, especially when you don’t know what to look for. Below are a few major signs of a silverfish infestation:

Silverfish droppings

Every living creature exudes some kind of waste, including silverfish. Their droppings are small, spherical in shape and black in colour. It can often be found where they eat, including in stacks of paper, books, or packages of pasta or bread.

Paper damage

Since silverfish love paper, an obvious sign of their presence in your home is finding damaged paper or cardboard items such as storage boxes, wallpaper, or books. Pay close attention to food containers filled with starchy carbs. If something is eating away at your cereal box, you probably have a silverfish infestation.

Shedded skin

Like many other insects, silverfish shed their skin as they go through their lifecycle. Considering their size, the shedded skin is often difficult to detect. The most likely places to find these would be in the kitchen, bathroom, or basement.

Seeing a live specimen

Most people think that seeing a single bug proves nothing but what they don’t realise is in most cases, a single bug is a sure sign there are many more you don’t see.

How to get rid of silverfish?

Eliminating silverfish requires a multi-step approach, combining environmental control, natural remedies, and professional intervention if necessary. These pests are resilient, so a consistent effort is key to completely eliminating them.

1. Reduce humidity levels

• Silverfish thrive in humid environments, so reducing moisture in your home is the most effective long-term solution.
• Use dehumidifiers in damp areas like basements, bathrooms, and kitchens.
• Improve ventilation by using exhaust fans in rooms prone to moisture buildup.
• Fix leaky pipes, taps, and drains to eliminate excess moisture.

2. Remove food sources

• Silverfish feed on starches and sugars, so cutting off their food supply helps eliminate them.
• Store dry foods like flour, pasta, and cereals in airtight containers to prevent contamination.
• Keep books, papers, and old magazines in sealed plastic bins rather than cardboard boxes.
• Wash and store clothing properly, as silverfish can damage natural fabrics like cotton, silk, and linen.

3. Seal entry points

• Silverfish can enter homes through tiny cracks, gaps, and crevices in walls and floors.
• Use silicone caulk or sealant to close off gaps around windows, doors, and plumbing fixtures.
• Install door sweeps and weather stripping to prevent silverfish from sneaking in through doorways.

4. Use silverfish traps

• Set up sticky traps in areas where silverfish activity is common, such as bathrooms, basements, attics, and storage spaces.
• Try DIY glass jar traps by wrapping a glass jar with masking tape and placing a starchy food source inside—silverfish climb in but cannot escape the smooth interior.
• Monitor and replace traps regularly to track infestation levels.

5. Apply natural silverfish repellents

• Diatomaceous Earth (DE) natural powder dehydrates and kills silverfish upon contact. Sprinkle DE in corners, under sinks, and along baseboards.
• Silverfish dislike the smell of cedar, so placing cedar blocks, sachets, or essential oil diffusers around infested areas can repel them.
• Lavender and Citrus Oils are strong-smelling essential oils that act as natural deterrents. Mix a few drops with water and spray in silverfish-prone areas.

How to prevent silverfish?

Preventing silverfish is easier than getting rid of an existing infestation. By making your home less attractive to these pests, you can avoid costly damage and maintain a silverfish-free environment.

1. Control humidity in your home

• Keep humidity levels below 50% using dehumidifiers, air conditioners, or exhaust fans.
• Open windows and doors regularly to improve airflow and reduce moisture buildup.
• Fix leaky taps, pipes, and drains to remove unnecessary moisture sources.
• Use moisture absorbers in closets, pantries, and other confined spaces.

2. Keep your home clean and clutter-free

• Silverfish love dark, undisturbed areas, so reducing clutter makes your home less inviting.
• Vacuum carpets, furniture, and baseboards to remove dust, food crumbs, and silverfish eggs.
• Dispose of old newspapers, magazines, and cardboard boxes, as these provide a food source and hiding spots.

3. Store books, clothing, and paper properly

• Keep important documents, books, and photo albums in airtight plastic bins instead of cardboard boxes.
• Wash and store clothing in sealed storage bags to prevent silverfish from feeding on natural fibres.
• Rotate stored items regularly to prevent dust buildup and nesting opportunities.

4. Use natural silverfish repellents

• Place cedar blocks, lavender sachets, or citrus peels in wardrobes, cupboards, and storage spaces.
• Use essential oil sprays with lavender, citrus, or tea tree oil around the home to deter silverfish naturally.
• Sprinkle diatomaceous earth (DE) or boric acid in potential entry points and damp areas to keep silverfish away.

5. Seal cracks and gaps around your home

• Inspect and seal small openings in walls, floors, and around pipes to block silverfish entry.
• Use caulking or weather stripping around windows, baseboards, and doorways.
• Repair damaged wallpaper and peeling paint, as silverfish often hide behind loose wallpaper.

6. Keep pantry and food storage secure

• Store cereals, flour, rice, and pasta in airtight glass or plastic containers to prevent contamination.
• Regularly inspect pantry shelves for crumbs or food debris that could attract silverfish.
• Avoid storing pet food in open containers; use sealed bins instead.

7. Schedule regular home inspections

• Conduct routine checks of attics, basements, and storage areas for signs of silverfish activity.
• If you notice increased humidity or moisture buildup, take action immediately to reduce it.
• If silverfish persist despite prevention efforts, consider hiring a professional pest control service for regular inspections and treatments.

Are silverfish harmful?

Silverfish are not directly harmful to humans as they do not bite, sting, or spread diseases. However, their presence can be a major nuisance due to their destructive feeding habits. These pests thrive on starchy materials, damaging books, wallpaper, essential documents, clothing, and stored food. Over time, an unchecked silverfish infestation can damage valuable items, particularly in homes with libraries, historical documents, or delicate fabrics. Their ability to consume glue, paper, and textiles is a hidden threat to personal belongings and household materials. They can also contaminate food storage areas, making dry goods such as flour, cereals, and pasta unfit for consumption.

Beyond material damage, silverfish can trigger allergic reactions in some people. Their shed skins, scales, and fecal matter contribute to dust buildup, aggravating respiratory conditions like asthma. While they are not known to transmit bacteria or viruses, their rapid reproduction rate makes them challenging to control once an infestation is established. A female silverfish can lay up to 100 eggs, allowing populations to spread quickly in dark, humid environments. If left untreated, silverfish can become a persistent problem, so preventative measures such as moisture control, sealing entry points, and regular cleaning are essential to keeping them out of your home.

Still worried about silverfish in your home?

While preventative methods are helpful when it comes to controlling silverfish, if you do have or suspect an infestation, it is best to call in the experts to provide professional treatment.

If you have or suspect a pest problem or would like to know more about protecting your home from pests, contact Rentokil today.