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Silverfish Fact Sheet

Pest biology

There are two species in the UK: silverfish and grey silverfish. Silverfish adults are approximately 10 -12mm long and silver; grey silverfish adults are 15-19mm long, motley grey and somewhat hairy. Their abdomens are tapered giving them a fish like appearance, hence their name. They are nocturnal insects.

Silverfish need a high level of humidity to survive so are usually found in moist or damp areas such as kitchens, bathrooms, under floors and basements.

You might notice:

  • Insects moving rapidly when lights are turned on in a dark room
  • Damage to wallpaper, books or other such materials
  • Scales, excrement or yellow stains on paper or fabrics
  • Seeing the insects (dead or alive) when they become trapped in sinks or baths

Problems they cause

Silverfish are more of a nuisance rather than a detriment to human health. They eat a variety of food products, from oats to sugar to moulds. They will eat paper and glue and so can cause significant damage to old books and wallpaper. They could spread spoilage organisms to food products.

 Commercial control methods

  • Monitoring, using sticky traps
  • Cleaning and vacuuming
  • Dehumidifying
  • Application of a natural insecticidal dust into infested crevices and voids e.g. under kitchen units
  • Insecticide spray application around the perimeter of a room as a barrier to intercept silverfish moving from the wall voids
  • Insecticidal bait placement (for grey silverfish)

What you can do to help

  • Regularly vacuum cracks and crevices around the home to help remove adults, juveniles and eggs (dispose of the vacuum bag immediately)
  • Keep kitchens, bathrooms, basements clean and free from unnecessary clutter
  • Reduce moisture and humidity using ventilation, heating, dehumidifying
  • Store food in tight containers
  • Seal cracks and crevices

Silverfish Images