Firebrats and Silverfish: Spotting the Difference

Tiny holes in old books, yellow spots on newspapers, peppery droppings, and loose scales littering your sack of flour and boxes of cereal are all signs that your home may have a few unwelcome silverfish or firebrats. Catching sight of these creepy insects is a memorable event. Their long antennae, tail-like appendages, and scaly bodies could make anyone’s skin crawl.

These pests are incredibly similar, both in appearance and signs of infestation, so telling them apart can be challenging. A few key differences can help, so here’s a quick guide to determine which pest has been chewing on your library.

FIREBRATS

Lesser known but not less annoying, firebrats are easily confused for silverfish unless you know how to spot them. Firebrat adults grow to be ½ inch long, with greyish brown scales on their tapered, thin bodies. The variance in color on their tiny, carrot-shaped bodies produces a speckled or mottled look to their scales, often with a slight sheen.

Firebrats are part of a group commonly called “bristletail” insects due to the three antennae-like parts protruding from the rear of their abdomen. On the other end, they have two extended antennae that grow to be longer than the length of their bodies.

Firebrats can live impressively long, with a lifespan of about two years or more. Their long life is sustained by a diet of starches, sugars, and proteins. A few common firebrat meals include flours, sugar, dead insects, pet food, paper, wood, and objects containing adhesives or glues like book bindings and wallpaper.

These pests might leave clues to their presence by leaving behind yellowish stains and shed scales. If you do spot a firebrat in the flesh, they’re bound to dash away quickly in a sideways motion to their next hiding spot.

True to their name, firebrats love it when it’s hot. They’ll most likely be found in humid places where temperatures are likely to reach over 90° Fahrenheit, which means your oven, dryer, and water heater are favorite nesting sites for these pests. Because they’re nocturnal, they’re rarely spotted in the daylight and stick to hiding under appliances, crevices, and can even be found tucked beneath shingles on the roof when it’s hot out. Though they’re frequently found in moist areas, they’re able to withstand dry heat, too, and can live in areas with humidity as low as 30%.

SILVERFISH

Silverfish have much in common with their lookalike cousin the firebrat. Their shiny bodies, however, have a grey-ish, silvery, or blue color. They’re similarly shaped and grow to be about the same size, but many silverfish can outgrow firebrats by a quarter of an inch, extending to about ¾ inch in length. Like firebrats, they’re also considered bristletails and will have the same tail-like appearance on the end of their abdomen, but their antennae don’t outgrow their bodies and will appear shorter or to be about the same length when fully grown.

These pests can outlive firebrats, too. Silverfish can live to be about three years old, and their hardiness doesn’t stop there. Several months with only water and no food or a few weeks without a drink won’t harm them a bit. When they do forage for a bite to eat, they look for items with a higher sugar or starch content like cereals, oats, and flours, and they share firebrats’ affinity for adhesives and paper, meaning your wallpaper, book bindings, and printed items are vulnerable to damage when these pests are around.

Just like their color, silverfish movements also give insight into their name. Nocturnal and quick, they maneuver their bodies sideways in a wriggling motion that resembles fish swimming. These movements take them to and from humid, moderate hiding places away from sunlight, such as cabinets, basements, under sinks, near bathtubs, and around pipes. Because they’re light-averse, you may not see a silverfish in person, but silverfish often leave traces of their habitation. In addition to chewed paper, if a box of cereal or old book suddenly looks like someone dumped what looks to be pieces of black pepper inside, you’ve probably seeing silverfish droppings.

WHY IT MATTERS

Signs of a firebrat or silverfish infestation look nearly identical, so discovering which pest is active will decrease the chance of incorrectly placed control methods that may not knock out the offender you’re looking for. To tackle the problem, here are some simple tips to bring you closer to a silverfish- and firebrat-free home.

  • PEST HUNTING. With a flashlight and a little extra determination, start investigating places these pests may be hiding, paying extra attention to the temperature of these hiding spots, as this may be the strongest clue in differentiating between firebrats and silverfish.
  • LOOK AT HABITATS. If silverfish are lurking near a leaking pipe or firebrats are parked near a humid dryer, take measures to make it a less pest-friendly spot. Repair pipes, plug in dehumidifiers and fans, and seal up crevices that may be housing these insects.
  • SIMPLE TRAPS. If you’ve hunted and still are not sure where these pests are hiding, place glass jars covered with sticky tape in places you suspect they’re lurking. The sticky tape on the outside will allow these insects to climb inside, but the slick surface of the glass inside is too smooth for them to escape. In a pinch, glue traps designed for cockroaches work, too, and the number of insects you catch could be a good indicator of how large a population you have on your hands.
  • DINNER. Ensure that food is stored in airtight containers and that all spills and messes are quickly cleaned up. Less-obvious spots need some TLC, too, so take the vacuum around the house and target cabinets, closets, beneath appliances, and on pantry floors. Seal the vacuumed contents tightly and toss them outside.
  • INFESTED ITEMS. If an old book, piece of fabric, or stack of newspapers have a few pests lurking inside, place them in an airtight bag and store them in the freezer to eliminate living pests. Clean well after removal.
  • DETERRENTS. Non-toxic powders like boric acid and diatomaceous earth work to dehydrate both silverfish and firebrats, so a sprinkling of either in places you suspect these pests can be an effective means of control. Be sure to follow the label instructions for proper application.

It can be tricky to determine whether you have silverfish or firebrats, so when in doubt, consider contacting one of our pest control professionals to properly identify and remove any bristletail insects invading your home. Our team of specialists can quickly identify any pest problems and prepare the best course of action to prevent your home from becoming a pest haven.

SOURCES

http://ipm.ucanr.edu/PMG/PESTNOTES/pn7475.html
https://agrilifeextension.tamu.edu/library/insects/silverfish-and-firebrats/
https://ento.psu.edu/extension/factsheets/bristletails-silverfish-and-firebrats
https://lancaster.unl.edu/enviro/pest/factsheets/005-94.htm
https://www.canada.ca/en/health-canada/services/pest-control-tips/silverfish-firebrats.html