There is a good chance you are close to one of these curious insects called silverfish. They can be anywhere, and survive on very little, and you have probably seen one hanging around when you are looking for something under the sink.
Silverfish are only considered a nuisance pest when they start breeding in homes. They are difficult to control there, and are well known for damaging books, wallpaper, photos, clothes, and even dried food in our pantry.
During the day they are hidden, but at night they come out searching for food. They tend to hang around in dark, damp environments, such as the bathroom or kitchen. Their constant presence can raise questions about how dangerous silverfish can be, and whether they can bite or sting us.
Are silverfish dangerous?
Although silverfish look scary, and are sometimes mistaken for poisonous centipedes, they are not actually dangerous to humans. They do not carry communicable diseases.
In most cases, silverfish flees instantly to safety when surprised. Even if you do catch one, you are likely to do far more damage to it than the silverfish can do to you.
Catching one is not easy because this insect is quite fast over short distances and can hide in cracks and crevices inaccessible to our fingers. In these same crevices, it usually stays during the day and comes out only at night.
While they are not dangerous to humans, the same cannot be said for their effects on our belongings. Silverfish leave small holes in the materials they bite, mainly paper objects.
Do silverfish bite or sting?
Entomologists doubt that silverfish bite people, as these insects have feeble jaws. So, they are not strong enough to pierce the skin of a human being.
However, it can be easy to confuse silverfish with another insect, earwigs. Along with spiders, earwigs are among the natural predators of silverfish and can be found in the same environments.
The rear pincers of earwigs are capable of light stinging, as are the jaws of some spiders.
Although silverfish jaws do not pierce our skin, they can be used to damage our homes. They use them to scrape and chew through paper, fabrics, and even our food, leaving a yellow residue in their wake, which is their faeces.
Since silverfish are nocturnal and quite elusive, seeing these yellow marks is often the first sign of a silverfish infestation.
Can silverfish cause allergies?
Silverfish, like most insects, renew their skin as they age. In fact, they lose their silvery colour and the larger ones become darker, even turning almost black.
The dried skins of dozens of minnows (their exoskeletons) turn to dust in our homes. This dust ends up suspended in the air and causes allergic reactions in some sensitive people. This is like what happens with dust mites.
Studies indicate that silverfish stimulate respiratory problems in people who are already allergic to common indoor allergens.
Are silverfish harmful to pets?
Some of our pets enjoy playing with whatever tiny creatures they find indoors or outdoors. Cats engage in this behaviour, due to their hunting instinct and their curiosity.
If our pets find a silverfish, they will often just play with them or give them a swat. But sporadically, they become overly curious and start to wonder if they can be used as food.
Silverfish run up and down walls and can easily attract the attention of pets. Being quite fast and agile, they can become a tempting target for the eyes of a pet looking for prey.
Fortunately, silverfish do not cause disease in pets, even if ingested. They also do not possess dangerous toxins, nor can they bite or sting our pets.
Can silverfish damage my things?
Silverfish can digest cellulose on their own, so they can eat wood and paper without difficulty. But they also feed on other substances containing polysaccharides, such as starches and the dextrin in adhesives.
The latter makes them prefer book bindings, carpets, clothing, coffee, dander (human and pet), glue, hair, some paints, paper, photos, plaster, and sugar.
Other substances they may eat are cotton, dead insects, linen, silk, leftover crumbs or even their skin after moulting. They have been known to eat even synthetic fabrics in cases of need.
If there is sufficient moisture, silverfish can live for a year or more without eating. And when they find a food source, they try to nest as close to it as possible. So, they will concentrate in damp places with carpets or fabrics, or even in pipes.
If you find an infestation of silverfish, contact a pest control professional. Once established in a favourable location, their population grows rapidly, and they can be difficult to control, which will multiply the damage caused to your belongings or home.