Can Silverfish Swim?

If you live in a house with a shower or bathtub, you may have encountered a shiny, disturbing little insect chilling out in the place where you plan to wash yourself. These little cockroach-esque things are called Silverfish, and with them always seeming to appear from the drains, many have wondered; can Silverfish swim?

Silverfish, despite their colloquial name, are not fish and cannot swim. In fact, whilst they typically make their habitat in moist places and have a fish like appearance, they hate water and will readily drown when exposed to it.

So, despite having ‘fish’ in their name, these little creatures are actually insects and have no ability to swim. But something about these things, whether it be their strange appearance or lack of general knowledge about them, has inspired urban legends on what these creatures can and cannot do. Let’s discuss some fact and fiction about these creatures to try and get a handle on them.

Why Are They ‘Silverfish’ If They Can’t Swim?

There is no one exact reason that can be pinpointed as to why these little bugs are called ‘Silverfish’ when they are insects who hate water, but several theories have floated around as to why people may have chosen this strange nomenclature for them.

  1. They have a fishy like shape, with a bulbous top head and a smaller tail end.
  2. They are very scaley and often shiny grey, which also may look like fish.
  3. They are often found in moist areas, especially where drains or leaks have appeared, giving people the impression the creatures may have swam to be where they are.
  4. When they crawl around, they may look as if they are swimming.

In other words, the bugs themselves have nothing to do with fish or even water; it is only by appearance alone that people have chosen that name for them.

Since not many people know as many details about these household pests as others, the rumours about these creatures go beyond swimming.

Can Silverfish Fly?

Sounds bizarre, but in amongst the urban legends about these little things, rumours have established that they may be able to fly.

However, Silverfish have no ability to fly. They have no wings and are therefore not able to get anywhere from flying. They do enjoy damp places, though, and on some occasions, Silverfish may fall from a damp attic into a lower room, which may have been the source of the flying rumour.

Another possible reason some people may think they can fly is because Silverfish hate light, and will scuttle away when a light in a house is turned on. This, and their appearance might have them mistaken for cockroaches, which are infamous for flying.

Can Silverfish Bite People?

You can stop panicking and put down that can of bug spray, because despite some rumours abounding around Silverfish, they are not known to bite people. In fact, whilst annoying, they’re generally considered harmless unless you have a true infestation of them in your home, and even then, the worst they can be considered is expensive for most people (Unless you have asthma – but we’ll get into that later!). Some quick rumour busting to help you sleep tonight if you were worried:

  • Their jaws are thought to be too small to pierce human skin, so even if they tried, they couldn’t bite you
  • Of course, this means that unlike other pests like lice and mosquitoes, human blood has no part in their diet
  • They have no venom in them and are not poisonous – you or even your fur babies could eat them and it would technically do no harm
  • There are no associations between Silverfish and diseases, so even the worst infestation won’t get you sick.

So, those are the major things that Silverfish are thought to be able to do but can’t. Now, let’s talk about some of the things Silverfish can do.

Silverfish Can Climb as Fast as They Can Crawl

Silverfish may not be able to swim, but they can climb. In fact, they can climb extremely well, as fast up a vertical plain as they can crawling across a horizontal one, according to some reports.

This is definitely true for rough surfaces, such as wood or grass, but their ability to climb fails them on extremely smooth or slippery surfaces, hence why in the bathtub example from the introduction, the Silverfish may just have been hanging out inside the bathtub instead of climbing to freedom.

Silverfish Can Jump Up To Two Feet Vertically

You read that right. According to pest control experts, Silverfish have been known to jump up to two feet vertically when disturbed. Considering that the high end of average length for a Silverfish is 25mm, and 2 feet is 60cm, that is almost 24 times their own length vertically. For more context, that would be like a 183cm human jumping 4,392cm from a standstill. Isn’t nature terrifying?

The reason for this leaping ability is apparently, instead of using their six little legs to perform the jump, they use their thick abdomen.

Silverfish Can Eat All Sorts of Things Which Will Cause You Trouble

Yes, unfortunately, just when these strange little creatures were starting to look incredibly benign, I have to break this news to you; what they eat in your house is very likely to cause you a great deal of trouble if you have a huge infestation of them.

Just some of the things Silverfish have been known to eat are:

  • Books
  • Carpets
  • Wallpaper
  • Paintings
  • Bedding
  • Clothes
  • Photographs
  • Shampoo
  • Soap
  • Lotion
  • Mould
  • Human Hair

Yes, you read that last one right. Silverfish love the protein that is found in your hair, so whilst they cannot and do not want to bite human beings’ skin, they find your hair nearly irresistible. Fun fact: if you have a dandruff problem, then the chances of a Silverfish having crawled across your scalp whilst you sleep to get to that tasty, tasty hair has become more than likely. Sweet dreams.

Silverfish Can Outrun Most Other Insects, Including Spiders and Centipedes

Another fun fact about Silverfish is that they are thought to have come into existence around 400 million years ago. For context, the dinosaurs were thought to have been around since 240 million years ago, so they must have been doing something right for all that time.

One of its main tools for survival is its incredible speed, which means it can outrun both centipedes and spiders, both of whom are fond of eating Silverfish.

The theory as to why they can outrun even an insect with so many more legs is their body, which moves back and forth in their strange swimming motion. It’s thought that this makes them much harder to catch, alongside their jumping ability.

Silverfish Can Shed Their Skin for Their Whole Lives

Moulting for insects is not that much of an unusual thing, but what makes Silverfish unique is that most insects will only moult their exoskeleton until they reach full maturity, which allows them to grow. Silverfish will continue to moult until the day they die, performing no real transformation each time they do it – which is a cycle only seen in some of the earliest insects to appear on earth.

This is likely of interest to a human like you for two reasons though:

  1. Their shed skin is one of few signs of an infestation, should you have one. Unlike other bugs, they do not bite, only come out at night, and their leavings are often too small to notice, so shed skin is one of the best signs.
  2. If you have an infestation, then as well as some nibbled books (and hair!) their shed skin may be hazardous to people who have asthma or particularly bad allergies, so watch out for that.


Silverfish, despite their confusing name, cannot swim and in fact, will drown in water. They cannot fly or bite either, regardless of what rumours may say. However, they can do all kinds of other things, such as climb, jump, outrun predators and eat your hair. Finally, even though these little things are ugly as sin, they are generally considered benign until there is a full-fledged infestation in your home, at which point they are a nuisance at best, and hazardous to people with allergies at worst.

Author Profile

Driven by a passion for those tiny creatures that rule our world, we at Bug Domain strive to be your go-to resource for information on insects.

Scroll to Top