Silverfish in NYC Apartments: What Causes Them and How to Eliminate Them for Good

A Pest Most New Yorkers Have Met

If you have lived in New York City long enough, you have encountered silverfish. That carrot-shaped, silver-scaled insect darting across your bathroom floor when you turn the light on at night, or the one that falls out of a book you have not opened in a year — silverfish are a persistent presence in NYC apartments that most tenants either ignore or do not realize are causing real damage. They are common in older buildings throughout Brooklyn (Park Slope, Carroll Gardens, Flatbush, Bay Ridge), Manhattan (Upper West Side, Harlem, Washington Heights), Queens (Astoria, Jackson Heights, Flushing), and The Bronx (Fordham, Pelham Bay, Mott Haven). They are not dramatic, and they are not dangerous — but the damage they cause accumulates silently over months and years.

What Silverfish Eat

Silverfish feed on cellulose and starch — two substances that are absolutely everywhere in a New York apartment if you know what to look for. Their food sources include:

• Books and paper: Silverfish eat the paper itself and the starchy binding glues used in paperback and hardcover books. A collection of books in a humid closet is essentially a silverfish buffet.
• Wallpaper adhesive: This is a significant issue in pre-war NYC apartments with original plasterwork and vintage wallpaper. The paste used in traditional wallpaper installation is a starch-based adhesive that silverfish consume over time, causing bubbling and separation.
• Clothing labels and natural fiber sizing: Wool, silk, and linen garments treated with sizing compounds are vulnerable. Silverfish do not typically eat the fabric itself in large quantities, but they consume the surface starches and can leave irregular surface damage on expensive natural fiber clothing.
• Dried pasta, cereals, and pantry staples: Silverfish will enter improperly sealed pantry storage and consume dried goods.
• Leather bookbindings and picture frame paste.

They do not bite, sting, or transmit disease. The harm is entirely property damage — but that damage accumulates silently, and by the time you discover it, an irreplaceable book or a silk garment may already be compromised.

Why NYC's Older Buildings Are Perfect Silverfish Habitat

Silverfish need 70 to 90 percent relative humidity to thrive. Below about 50 percent humidity, they cannot survive long-term. The building stock from the pre-war era through the 1970s — which makes up a huge proportion of NYC's residential units across all five boroughs — has accumulated decades of moisture penetration, aged plumbing, and inadequate vapor barriers. The result is chronic, building-level humidity that makes these structures essentially permanent silverfish habitat.

In summer, wall voids in buildings from Park Slope to the Grand Concourse in The Bronx maintain relative humidity well above what silverfish need. The pipe chases, elevator shafts, and utility corridors that connect apartments throughout a building allow silverfish to travel the entire structure. A silverfish population that originates in a building's basement or boiler room can reach upper-floor apartments through plumbing walls over time.

Pre-war buildings in Harlem, Washington Heights, and the Upper West Side with their original plumbing and steam heat systems have specific humidity patterns — areas near radiators and steam pipes experience cycling moisture that creates micro-environments ideal for silverfish nesting.

Where Silverfish Are Found in NYC Apartments

Silverfish hide during the day and forage at night. You are most likely to encounter them in these locations:

• Bathrooms: Behind vanities and under sinks — the combination of moisture from plumbing and the starchy paper products many people store in bathroom cabinets (toilet paper packaging, cardboard boxes) creates ideal conditions.
• Closets and storage areas with infrequent traffic: Undisturbed closets are prime silverfish habitat. The combination of low disturbance, stored clothing, and archived documents makes them ideal. In Astoria and Jackson Heights apartments where residents often use bedroom closets as long-term storage, silverfish populations can establish and go completely unnoticed for months.
• Kitchen cabinets near the plumbing wall: Especially cabinets under the sink and those adjacent to the wall shared with bathroom plumbing.
• Bookshelves and home library collections: Books are both food and shelter for silverfish. They nestle between books and behind shelf paper.
• Inside cardboard boxes in closets and building storage rooms: Cardboard is both a food source and a nesting material. Any long-term cardboard box storage is high-risk for silverfish activity.
• Above drop ceilings and inside walls adjacent to bathroom and kitchen plumbing: The interior void spaces of NYC apartment buildings are heavily populated with silverfish that descend into units through gaps in plumbing penetrations.

Signs of Silverfish Damage

By the time you see a silverfish, property damage has likely already occurred. Look for these indicators:

• Irregular holes with notched or scalloped edges in paper: The damage pattern is distinctive — silverfish feed from the surface, leaving thinned, damaged areas with irregular margins rather than the clean holes a hole punch makes.
• Small holes in clothing labels and natural fiber garments: Check wool sweaters, linen shirts, and silk items stored in closets. Damage appears on areas with surface starch or sizing compounds.
• Yellow staining on paper and fabric: Silverfish feces and secretions can leave yellowish stains on paper and light-colored fabric near their feeding areas.
• Tiny black pepper-like droppings on shelves: Look for these on the surfaces of bookshelves and in closet corners. They are small but visible with a flashlight.
• Metallic silver scales: Silverfish shed scales throughout their environment. Finding these on shelves or in cabinet drawers is a direct sign of activity.
• Live insects when disturbing storage: Moving a pile of old magazines or an archived box and having insects scatter confirms an active infestation.

The Moisture Root Cause You Cannot Ignore

Treating silverfish without addressing the moisture conditions that sustain them produces only temporary results. The professional treatment eliminates the current population, but the same building conditions will support a new one within months. In NYC apartments, moisture management means:

• Fix dripping pipes under sinks in writing to your landlord: Document the request. In NYC, building owners are responsible for conditions that contribute to pest infestations. A written repair request creates a record.
• Run your bathroom exhaust fan during and for 30 minutes after every shower: This is the single most impactful thing you can do to reduce bathroom humidity.
• Use a dehumidifier in closets and storage rooms running above 60 percent humidity: A small dehumidifier in a storage closet can maintain humidity below silverfish survival thresholds.
• Address known building-level moisture issues through management: If your building has a persistently damp basement or known plumbing issues in shared walls, report them formally and follow up. Silverfish coming from building infrastructure cannot be fully controlled at the apartment level.

Professional Treatment for Silverfish in NYC Apartments

Surface-level retail sprays are ineffective against established silverfish infestations. Silverfish shelter in wall voids and inaccessible spaces between treatments — a contact spray that kills exposed individuals leaves the population in the walls untouched. Within days, new individuals emerge and activity resumes.

Effective professional treatment uses:

• Dust applications in wall voids and pipe chases: Insecticidal dust applied through small access points into the spaces silverfish inhabit between treatments. This is the key step that retail products cannot replicate.
• Residual spray along baseboards and in closets: Applied to the surfaces silverfish must cross, creating lasting contact exposure.
• Gel bait in harborage areas: Some formulations include silverfish attractants that draw individuals from hiding to consume the bait.

For established infestations in older buildings, multi-treatment programs spaced two to four weeks apart are typically required. A single treatment visit is usually insufficient. If your building has a silverfish population in its shared infrastructure, ongoing maintenance treatment rather than one-time elimination is the realistic expectation — but professional treatment dramatically reduces indoor activity to manageable levels.

Prevention Checklist for NYC Renters

• Store books, important documents, and archival materials in sealed plastic containers rather than cardboard boxes or open shelves in humid spaces
• Store natural fiber clothing (wool, silk, linen) in sealed garment bags in closets with humidity control
• Use a dehumidifier in any space that maintains humidity above 60 percent — basements, storage closets, bathrooms without functional exhaust fans
• Fix all plumbing drips and report them to your landlord in writing
• Run your bathroom exhaust fan consistently — during every shower and for 30 minutes after
• Switch from cardboard box storage to sealed plastic bins, especially for items stored long-term
• Regularly inspect stored items in closets and under sinks — catching silverfish damage early limits how much is lost

When to Involve Your Landlord

If silverfish activity in your apartment is clearly coming from building infrastructure — pipe chases, basement moisture, or shared wall voids — you have grounds to put a written pest complaint on record with building management. NYC building owners are responsible under the Housing Maintenance Code for conditions that allow pest infestations to develop in common areas and building systems. If management does not respond adequately, a 311 complaint creates a formal record of the problem. Document the infestation with photos before and after any treatment visits.

Frequently Asked Questions

How fast do silverfish reproduce? Slowly compared to cockroaches or mice — silverfish produce roughly one generation per year and eggs take several weeks to hatch. However, individual silverfish live up to eight years, and established populations in the building infrastructure can persist for decades without intervention. Low reproduction rate does not mean easy control — it means infestations develop slowly and silently.

Can silverfish spread between apartments? Yes. Through shared pipe chases, wall voids, and utility corridors, silverfish populations move through multi-unit buildings freely. If multiple tenants in a building are reporting silverfish, the source is likely in the building's shared infrastructure, not in individual apartments.

I have had silverfish for years — is it too late? No. Established populations require multi-visit professional treatment to significantly reduce activity, but even long-standing infestations respond to professional programs. The more important step is addressing the moisture conditions that sustain them alongside treatment.

If silverfish are appearing in your NYC apartment — especially if you have seen damage to books, clothing, or paper goods — call NYC Pest Control Near Me at (917) 203-6158 for a professional assessment. We serve Park Slope, Carroll Gardens, Flatbush, Bay Ridge, Upper West Side, Harlem, Washington Heights, Astoria, Jackson Heights, Flushing, Fordham, Pelham Bay, and all five boroughs.