Silverfish are flat, silvery grey, shiny, completely wingless insects, which can grow up to approximately 12 mm long. They are nocturnal, agile and linked to moisture, which is why they can be found predominantly in bathrooms, kitchens, cellars, utility rooms, etc. They are characterised by long antennae and their tail threads, which are approximately 3 mm long. As far as diet is concerned, they are not particularly fussy – they prefer substances which are rich in carbohydrates, particularly sweets, but also live off flakes of skin, dirt particles and mould. Adult creatures can live for up to 5 years under optimum conditions. As part of the Apterygota subclass, they will shed their skin several times during this period as imagines. They can fast for up to 10 months.
Silverfish are harmless in themselves. However, their presence is an indicator of an elevated level of humidity and mould infestations in buildings as they also feed on mould if it is present. The creatures themselves only cause problems if they occur en masse and can cause damage, e.g. scraping or holes, to foodstuffs, wallpaper, book covers, pictures, leather goods or textiles when they feed.