You switch on the bathroom light late at night and something small and silvery shoots under the bathtub. Or you pull an old moving box out of the wardrobe and find tiny grey insects scurrying across the cardboard. Welcome to one of the most common pests in German flats: Silberfische, silverfish, and their bigger, tougher cousin, the Papierfischchen (paper silverfish).
First, the reassuring part: silverfish don't bite, don't sting and don't spread diseases. Finding them doesn't mean your flat is dirty. But a growing number of German households now deal with paper silverfish, which are harder to get rid of and can damage books, documents and photos.
This guide explains how to tell the two apart, which remedies actually work (and which home remedies are a waste of time), the cheap tools that help, and what to do if your landlord needs to get involved.
Germany has two common "fish" insects in homes, and they need different strategies. Most guides only talk about the classic silverfish, which is why many people try everything and still see them every night.
Quick test: if you mainly see them in the bathroom at night, you're probably dealing with classic silverfish. If you find them in the bedroom or living room, near bookshelves, or during the day, think paper silverfish.
According to the German Environment Agency (Umweltbundesamt), paper silverfish have become much more common in German homes in recent years. They spread mainly through cardboard: online-shopping parcels, moving boxes and packaging material. If you moved to Germany recently and brought or bought a lot of boxes, that may be exactly how they got in.
Before you buy anything else, place a few sticky insect traps along the skirting boards (Fußleisten), under the bathtub, behind the toilet and next to bookshelves. Check them after a few days.
The traps won't solve an infestation on their own, but they show you where the insects come from and how many there are. That tells you where to focus, and later whether your measures are working. If you need to involve your landlord or a pest controller, a few full traps are also useful evidence.
For classic silverfish, this is the most important step, and often the only one you need. The Umweltbundesamt notes that silverfish can only multiply in large numbers when humidity stays above about 75%. In most cases, improving the indoor climate alone makes the problem shrink.
The catch: you can't feel whether your bathroom is at 55% or 80%. A digital thermo-hygrometer shows you. Aim for 40 to 60%, the same range that also protects you from mold.
How to bring the humidity down:
If your bathroom has no window, or the hygrometer keeps showing more than 60%, an electric dehumidifier makes a big difference. A small model is enough for most bathrooms and storage rooms. For wardrobes and small closed spaces, a moisture absorber box works without electricity.
For more on airing and humidity, read our guide to preventing mold (Schimmel) in your German flat.
Silverfish spend the day in narrow gaps and come out at night to feed. Fewer hiding spots means fewer silverfish, and this matters even more for paper silverfish, which don't care much about humidity.
Fill gaps behind skirting boards, cracks in tile grout and open joints around the bathtub and shower. For gaps along walls and skirting boards, use paintable acrylic sealant (Acryl). For wet areas in the bathroom, use sanitary silicone with mold protection. Small fixes like these are usually fine in a rental, but ask your landlord before larger work.
Silverfish often come in through bathtub and sink drains. The Umweltbundesamt suggests closing them overnight. Simple silicone drain stoppers do the job and cost very little.
Cardboard is food, shelter and a transport system for paper silverfish all in one. This is especially important for expats who've just moved:
Tip for valuable paper items: books, letters or photos that may be infested can be put in a sealed freezer bag and frozen for several days. The cold kills the insects and their eggs.
If you still catch lots of silverfish after a few weeks of drier air and fewer hiding places, bait is the next step. Silverfish bait boxes (Köderdosen) contain an attractant mixed with an insecticide. The insects eat it and carry it back to their hiding spots.
A low-chemical option some people prefer is diatomaceous earth (Kieselgur), a fine powder dusted thinly into gaps and behind skirting boards. It works physically by drying out the insects. It can help as an extra measure but works slowly. Use it sparingly and don't breathe in the dust.
Search for Silberfische Hausmittel and you'll find plenty of tips. Here's an honest look at the most popular ones:
A few silverfish in the bathroom are normal and not something your landlord needs to fix. It's different when there are lots of them, or when you have paper silverfish:
Call a professional pest controller, or ask your landlord to, if:
Professionals use stronger bait gels and know where to place them. The Umweltbundesamt recommends professional help for paper silverfish in particular, because they're very difficult to control on your own. Look for a member of a recognised trade association, such as the Verband für Schädlingsbekämpfung (vfoes).
Are silverfish dangerous? No. Silverfish don't bite, sting or transmit diseases. Classic silverfish are mainly a sign of too much moisture. Paper silverfish can damage paper, books and photos, but they're not a health risk either.
Do silverfish mean my flat is dirty? No. Even very clean flats can have them. They're attracted by moisture, gaps and cardboard, not by dirt.
Why do I see silverfish in my bedroom? Classic silverfish prefer damp rooms, so if you see them in dry rooms like the bedroom or living room, they're probably paper silverfish. Check for cardboard boxes, bookshelves and gaps behind skirting boards.
How did silverfish get into my new flat? Paper silverfish often arrive in cardboard: moving boxes, parcels and packaging. Classic silverfish can also come through drains or from neighbouring flats.
Can I get rid of silverfish for good? Classic silverfish usually disappear once the humidity is under control and gaps are sealed. Paper silverfish are more stubborn and often need bait over several weeks, sometimes with professional help.
Who pays for pest control in a rental flat? If the infestation is caused by the building, such as moisture damage, it's generally the landlord. Report it in writing and get advice from a Mieterverein if there's a dispute.
Disclosure: Product links in this article are affiliate links. If you buy through them, Newsworm may earn a small commission at no extra cost to you.
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