Silverfish 

Silverfish are small, primitive, wingless insects recognised by their flattened bodies, scales and quick, agile movements. They are members of the insect order Thysanura and are well adapted to living in quiet, undisturbed areas. In Australia, silverfish are commonly found in buildings where they can shelter in places such as bookcases, storage areas, cupboards, roof spaces and ceilings. They can cause damage by feeding on materials containing starches and other organic substances, including paper, books, fabrics, wallpaper and some stored items. Although silverfish do not pose a direct health threat to people, their presence can become a concern when they establish themselves indoors and begin damaging household or business belongings. Understanding where silverfish hide and what attracts them is an important part of preventing and controlling an infestation.

Silverfish are small, wingless insects with a flattened, slender body covered in fine scales. Their bodies are usually silver or grey in colour and taper towards the rear, giving them their distinctive fish-like appearance. They have long, slender antennae at the front of the body and three noticeable tail-like appendages extending from the abdomen. These three rear appendages are one of the most recognisable features of silverfish. Young silverfish have a similar body shape and appearance to adults, but are smaller. Unlike many other insects, they do not undergo a complete metamorphosis, so the young gradually develop into adults while retaining the characteristic silverfish shape.

Silverfish have a simple development cycle and do not undergo the complete metamorphosis seen in many other insects. Females lay eggs individually or in small groups, with eggs generally hatching within 2–8 weeks. Young silverfish resemble smaller versions of the adults when they emerge. They grow through a series of moults, gradually increasing in size as they develop. Sexual maturity is generally reached after approximately 3–24 months, depending on conditions. Unlike many insects, silverfish continue to moult periodically throughout their adult lives and may live for up to four years, allowing established populations to persist for extended periods where suitable food, shelter and environmental conditions are available.

Silverfish are fast-moving, nocturnal insects that are generally active at night and tend to avoid light. During the day, they seek shelter in dark, quiet and relatively undisturbed areas. They can move throughout a building in search of food and suitable shelter, which means they may be found in a variety of rooms and storage areas rather than remaining in one location. Common hiding places include cupboards, bookcases, storage areas, roof spaces and other secluded parts of a property. Silverfish are unable to climb smooth vertical surfaces effectively. As a result, they can sometimes become trapped in smooth-sided baths, sinks and basins, making these locations a useful indication that silverfish may be active elsewhere in the property.

Silverfish can become a problem when they establish themselves inside homes, businesses or other buildings. They can shelter in a wide range of concealed areas, including roof cavities, wall voids, subfloor spaces, cupboards and other undisturbed parts of a property. Silverfish are attracted to materials containing starches, glues and other substances used in paper products and furnishings. They may damage books, book bindings, photographs, wallpaper and fabrics such as cotton and linen. Paper and photographs can be particularly vulnerable, with the smooth or treated outer surface sometimes showing signs of feeding damage. Because silverfish are active at night and can hide during the day, an infestation may go unnoticed until damage is discovered or silverfish are regularly seen indoors. Controlling an established population can help protect books, documents, furnishings and other valuable items from further damage.

Effective silverfish management begins with identifying where activity is occurring and the conditions that are allowing silverfish to remain within the property. Because silverfish may be distributed through roof cavities, wall voids, subfloors, cupboards, storage areas and other concealed locations, successful management may require a combination of professional treatment, environmental management and preventative measures. The appropriate approach will depend on the extent of the activity, the areas affected and conditions within the property. PROFESSIONAL PEST MANAGEMENT Professional silverfish management begins with a thorough inspection to identify areas of activity and potential harbourages. Stored articles and other undisturbed areas may need to be examined to determine where silverfish are sheltering and feeding. Depending on the location and extent of the infestation, professional management may include appropriate treatments to areas where silverfish are likely to shelter or travel, including concealed or difficult-to-access locations where suitable. Different treatment methods and products may be selected according to the circumstances of the property, the areas requiring treatment and the level of silverfish activity. Professional silverfish management is most effective when inspection, appropriate treatment and preventative measures are combined to address both the silverfish and the conditions that allow them to persist. PREVENTION & NON-CHEMICAL RISK MANAGEMENT Reducing the conditions that attract and support silverfish can help prevent activity and reduce the likelihood of an infestation becoming established. Check second-hand books, furniture and other stored items before bringing them into a home or business, as these may provide an opportunity for silverfish to be introduced. Books, documents, files and papers should ideally be stored in clean, dry and well-ventilated areas rather than being left undisturbed in tightly closed boxes or cupboards for long periods. Regularly opening and checking storage areas can help identify silverfish activity before significant damage occurs. Avoid excessive clutter and allow air to circulate around stored materials where practical. Valuable books, photographs and documents should be stored appropriately to reduce their exposure to potential pests. In kitchens and food-storage areas, keep food in sealed containers and clean up crumbs, spills and food scraps promptly. Regular inspection is particularly important in areas that are rarely disturbed. Early detection, appropriate storage and good housekeeping can all contribute to reducing the risk of ongoing silverfish activity.