Spotted a little silver thing wriggling in the sink or bath at night? Before you reach for the spray, here are five quick things worth knowing about silverfish.
1. What they actually are
Small, silvery, teardrop-shaped insects that move with a fast, fish-like wriggle. They're nocturnal, quick, and completely harmless: they don't bite, sting or spread disease. What they are a persistent nuisance, and a useful signal.
2. They're really a damp signal
This is the big one. Silverfish aren't a cleanliness problem, they're a moisture problem. They need humidity to survive, so if you're seeing them regularly, the house is usually telling you there's more damp somewhere than there should be.
3. Where they hide
Anywhere warm and damp: bathrooms, kitchens, under sinks, behind skirting, in cupboards on outside walls, and in cellars or lofts. You often find them stuck in the sink or bath because they've come for the moisture, fallen in, and can't climb back up the smooth sides.
4. What they damage
They feed on starches and sugars, so they'll nibble paper, wallpaper paste, book bindings, cardboard and dry stored food like flour and cereal. Usually slow and minor, but annoying if it's your books, documents or wallpaper.
5. Why the fix is moisture, not sprays
They hide deep in cracks and voids, so a spray only kills the one you can see while the rest carry on. The lasting fix is drying the place out: use extractor fans, fix leaks, add a dehumidifier in humid rooms, and seal the gaps they hide in. Sort the damp and they've no reason to stay.
A stray one now and then is nothing to worry about. Seeing them regularly, or finding damage to paper and wallpaper, usually means a silverfish infestation worth looking into. Clear Pest Control checks silverfish activity across the North East and helps pin down the damp behind it.
See our full guide on where silverfish hide and how to shift them .