Silverfish vs Cockroach – Everything You Need To Know

The issue of pests has plagued humans for centuries. Two of the most common pests that make their way into people’s homes are cockroaches and silverfish

This article is the definitive guide on silverfish and cockroaches. It will teach you everything you need to know, including the difference between the two species and how to treat an infestation. 

What is a Cockroach? 

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Cockroaches are a large species of insect defined by their reddish-brown color. They are resilient pests that can survive in extreme environments and have a reputation for being resistant to radiation and very hard to kill.   

Habitat and Environment 

Able to withstand extremely low and high temperatures, Cockroaches can survive in almost any environment, making them a common pest across the globe. However, cockroaches are most commonly found in tropical and sub tropic conditions. 

Cockroaches can typically be found in dead or decaying matter, amongst fallen leaves, behind tree bark, or rotting wood. 

Size and Anatomy 

Currently, there are over 4600 different species of cockroaches identified in the world. 

Depending on the species, a cockroach can range anywhere from the size of a thumbnail to a massive 10cm. The largest species, Megaloblatta longipennis, can grow to 10cm in length with a wingspan of 20cm.   

Cockroaches are defined by their small head and broad, flattened body. Two large eyes and a mouth part are located on the underside of the head, consisting of chewing mandibles, salivary glands, and taste and touch receptors.  


Thanks to their unique ability to last long periods without food or even air. The cockroach has earned a reputation as one of the most resilient insects on the planet.     

Depending on the species and sex, the lifecycle of a cockroach can range massively. Oriental cockroaches have an average lifecycle of anywhere between 160 to 180 days. In contrast, an American Cockroach can survive between 362 to 700 days

Sex also plays a role, with female cockroaches having a much longer lifespan than their male counterparts. 

What is a Silverfish? 

Silverfish are a species of small primitive flightless nocturnal insects. Their name derives from their silvery color and their movement, which mimics that of a fish

Habitat and Environment 

The silverfish can be found across almost all of the globe, including Africa, the Americas, Australia, and Eurasia

Silverfish require a moist habitat to survive, where the ambient relative humidity is between 75% to 95%. Silverfish are commonly found in bathrooms, basements, attics, classrooms, showers, sinks, and bathrooms in urban areas.     

Size and Anatomy 

Silverfish can range between 13–25 mm (0.5–1.0 in) in length. They can be identified by their long antenna and a pair of rear appendages known as cerci


Silverfish have a typical lifespan of three years and are photosensitive, meaning they avoid light.  

How to Tell the Difference Between a Silverfish and Cockroach?  

Visually the two pests are entirely distinct. Cockroaches are easily identifiable by their brownish color and broad, flattened body. Whereas silverfish are much more slender with a silvery grey color.  

Which is Most Likely to Visit Your Home?

That depends on the environment of your home. 

If your home, your attic, or basement is filled with old books and paper that is not stored correctly, you are more likely to get a visit from silverfish. Silverfish feed on paper and books, breaking down the starch in the paper into food.

Having books and paper stored incorrectly in your house may encourage a silverfish infestation

Cockroaches are a different matter. Like most other pests, cockroaches are attracted to food garbage. An unhygienic home with dirty dishes, incorrectly stored food, and not disposing of waste correctly can cause cockroaches to enter the house. 

But it is not just inside the home you have to worry about with cockroaches.

Some cockroach species can make their way into the house through the garden, seeking shelter in firewood. 

With people being unaware of how to correctly store paper or books and the typical cardboard boxes they are stored in, tend to rot over time, silverfish are more likely to invade the average home. 

What Are the Causes of a Cockroach Infestation? 

With cockroaches thriving in pretty much any environment, many factors can help attribute to a cockroach infestation. 

Food Debris 

As insects and pests, cockroaches are not fussy eaters. They will eat anything if given a chance. Leftover food, unwashed plates as well as improper storage of shelf-stable foods such as flour and sugar can all attract cockroaches. 

Pet Food 

The proper food storage is not just confined to humans. If given the opportunity, cockroaches will choose pet food over no food at all. Again the same rules apply. Any leftover pet food that has been sitting out overnight is likely to attract unwanted pests. 


Trash provides a significant food source for cockroaches. Trash cans contain not only discarded food but also dandruff, dead skin cells and other debris that cockroaches will happily feed off of. If your trash is not tightly sealed and disposed of correctly, it provides another way for cockroaches to enter the home.  

Moisture and Water 

Cockroaches are attracted to warm, humid climates. By reducing the humidity and drying any wet surface or materials as quickly as possible, you reduce the chance of a cockroach infestation. 


The garden is another way for cockroaches to enter the home. A cockroach’s natural habitat is amongst fallen leaves or dead branches of wood. Cockroaches can quickly be brought into the home if you are storing firewood outside or are not disposing of leaves and planet debris correctly. 

What Are The Causes of a SIlverfish Infestation? 

Humidity and Damp 

Silverfish are attracted to damp, humid areas. Bathrooms and kitchens provide the perfect breeding ground for silverfish due to the moist air and plethora of damp materials for them to breed in. 

Improper Storage of Paper and Old Clothing 

Silverfish are naturally attracted to paper and clothes, using the starch found within these items as a food source.  

Rotten Wood 

Silverfish hide their eggs in cracks and crevices. Rotten wood is not only filled with these small hiding holes, but if the rot is caused by damp, it provides the ideal environment for the eggs to live.  

Is One Worse Than the Other as a Pest?

While both pests are equally damaging to a household due to their resilience, cockroaches are by far the worse pest of the two. 

Do Cockroaches Eat Silverfish? 

Surprisingly, yes. Due to the diets of silverfish and cockroaches being very similar, the larger cockroach sees the smaller pest as a potential food source. 

Do Silverfish Eat Cockroaches? 

Silverfish are no natural predators. They feed on starch and carbohydrates. They do not eat other insects. 

How Do I Get Rid of Them?

With the cockroaches and silverfish plaguing humans for centuries, there are a whole host of treatments and remedies that can be used to get roaches out of your house. Here is an extensive list of proven methods

Baking Soda (Cockroach Only)

This common household item is one of the easiest and most effective remedies out there. Sprinkle a bit of baking soda onto a handful of onions as a way to attract the roaches.

Once consumed, the baking soda will create gasses that cause the roach’s stomach to burst.  

Essential Oils 

Another excellent roach repellent. Dilute essential oils like peppermint, lemongrass, lavender, and tea tree oils in water and spray them at the sight of the problem.  


Roaches and silverfish hate the smell of lemons. Next time you clean the floors, scent the water with lemon oil. The scent will drive the roaches nuts.  

Diatomaceous Earth

Otherwise known as DE, this natural insecticide is a highly effective way of dealing with pests.

Made of fossilized algae, DE reacts with the roaches and silverfish exoskeletons causing them to die from dehydration. Sprinkle DE on the surface where the roach activity is most prominent. 

Call an Exterminator

Sometimes an infestation is too large for one person to handle. If you find yourself in this situation, get a trained professional to do the job for you.  

How Do I Prevent an Infestation? 

If you have had the displeasure of dealing with a cockroach or silverfish infestation, odds are you won’t want to do it again.

To prevent another infestation from occurring or any at all, here is a list of measures that you can put in place to help reduce the chances of an infestation. 

  • Wash and put away all dirty dishes immediately after use. 
  • Store all shelf-stable foods, including sugar and flour, in airtight, plastic, or glass containers.
  • Ensure that any old papers, books, or clothes are stored in airtight containers.
  • Empty the trash daily and ensure that all trash bags are appropriately sealed
  • Pet food should not be left to sit overnight  
  • Mop, sweep, and clear floors and work surfaces regularly. 
  • Do not leave damp towels and mats around for long periods.
  • Reduce the humidity of your bathroom by opening a window when showering or buying an extractor fan. 

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Can Any Insects Survive in the Human Body? Things to Be Aware Of

Pest Control or Exterminator: Seven Key Things You Need to Know Before Choosing
13 of the easiest insects to keep – Plus Costs!

Steve Foster

Mad about bugs and wanting to publish as many articles as I can to help educate people about these amazing beautiful creatures! For more info check out my about page

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