Silverfish: Kinda Silver, Not a Fish

By Naomi Shanel Rubi and Tony Awad

CC: Francisco Welter-Schultes

If you’ve ever noticed a small silvery insect in your bathroom that did not look quite like anything you’ve seen before, you may have encountered a silverfish or Lepisma saccharina. Despite popular belief, these insects are not fish, but they do bear some similarities to certain fish that swam 400 million years ago. These ancient fish resembled nothing like your typical supermarket fish, but rather that scaly silvery insect in your bathroom. The similarities cannot be attributed to divergence from a common ancestor, but is instead a pure coincidence!

The scaly silvery hue of silverfish uncannily resembles the colorful and reflective scales of a fish. Silverfish and fish both love water. Whereas most fish live the entirety of their lives underwater, silverfish love warm moist environments, which is why they like to hang out in your bathroom after a steamy shower.

Silverfish enjoy a humid and warm climate of 70-80 degrees Fahrenheit. You may even think that these little creatures might also make perfect companions for daytime family road trips! Sadly, you might not be able to watch the sunset with them together on a beach as they are mostly nocturnal creatures and hide during the day.

Silverfish are one of the oldest kinds of insects to inhabit the Earth. The first record of silverfish can be traced back to over 400 million years ago, which is even older than dinosaurs!    Not only are they one of the most ancient insects, but they also have one of the most extensive lifespans. They shed their skins six or seven times before they are ready to settle down and raise a family and can live up to four years!

CC: Rinaldo R

Many sources may tell you that silverfish like to prey on cashmere sweaters. Actually these sweaters are safe because wool is made of protein, which is not on the silverfish menu. Silverfish prefer to dine on an exquisite selection of carbohydrates. For example, the wallpaper that you just hung in your newly renovated kitchen may contain starch.  Weirdly,  they might wash down a carbo snack with some your shampoo! If you’re trying to survive a zombie apocalypse, good luck to you because these little creepy crawlers often finish your unopened food storages before you get to even find out what food you stored in your safety bunker! Despite their unique diet, silverfish can live up to a year without food. If you were planning on trying to starve them to death, have fun waiting! Oddly enough, silverfish are pretty picky eaters. Their consumption of carbohydrates decreases as temperatures increase and they tend to consume a higher proportion of lipids and proteins as temperature increases. Silverfish sure are jocks at the beaches when it comes to perfecting that summer body!  

Silverfish are also highly acrobatic, able to scale walls and climb into sinks or bathtubs; however, once they decide to go for that fateful swim, they are unable to crawl back out. This makes it easy for pest control methods in the event you find them trying to take a shower in your home! No need to bust out any hazmat suits and insecticides, though: silverfish have been found to apparently hate essential oils.  

All in all, although silverfish may vaguely resemble a fish, their evolutionary history, feeding behaviors, and the way they wriggle prove that they are anything but.

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