The insect in the photo is a silverfish, a small wingless insect recognized by its silvery-gray body, long antennae, and three tail-like bristles. Silverfish are usually most active at night and prefer dark, humid places, which is why people often find them in bathrooms, basements, kitchens, laundry rooms, closets, and underneath sinks. Seeing one occasionally is not usually dangerous, but repeated sightings can be a clue that part of the home is staying more humid than it should.

Silverfish are attracted to moisture, but they also need food. They feed on materials containing starches and sugars, including paper, cardboard, wallpaper paste, book bindings, cereal, flour, and even some fabrics. That means a larger infestation can occasionally damage books, photographs, stored papers, wallpaper, or clothing. They do not bite people, spread disease in the way some pests can, or live on the human body, but their presence can still become frustrating if their numbers increase.

If you begin seeing silverfish regularly, the first thing to investigate is excess moisture. Check for leaking pipes, condensation, damp basements, poorly ventilated bathrooms, and water collecting beneath appliances or sinks. Using an exhaust fan or dehumidifier can make the environment less attractive to them. Vacuuming along baseboards, cracks, closets, and storage areas also helps remove insects, eggs, and food debris. Paper and cardboard should ideally be stored somewhere dry rather than directly on basement or garage floors.

So finding a silverfish doesn’t mean your house is dirty, and one insect isn’t necessarily a reason to panic. But it can be a useful warning that there is humidity, a hidden leak, or plenty of undisturbed material for them to feed on. If you continue finding them despite reducing moisture and cleaning thoroughly, it may be worth inspecting the home more carefully or contacting a pest-control professional to locate where they are hiding.