This post contains affiliate links. If you click & make a purchase, I receive a commission! Thanks! Questions? View my full disclosure.

The Super Shark Encyclopedia was a patient in my class’ book hospital the other day.  As I was flipping through the book, looking for pages to tape (and looking for a distraction from the endless noise of free play – blocks falling, cars rolling, dinosaurs roaring – Calgon, take me away!), I came across the Barrel Shrimp.  The description was intriguing.  The barrel shrimp is a translucent creature that eats the center of another creature then uses that remaining barrel shape as a floating stroller for its eggs.  I knew immediately that I needed to find out more about this shrimp.

barrel shrimp page of super shark encyclopedia phronima
  • Save
The barrel shrimp page of the Super Shark Encyclopedia by DK Publishing

My first research attempts

If you google barrel shrimp, you will get many results for an entree at Cracker Barrel.  Not exactly what I was looking for.  Adding animal to the search brings you closer but a lot of results are about shrimp in general as opposed to this barrel shrimp specifically.  Finally I found a link to the Plankton Chronicles website.  This site has a video of the barrel shrimp in action.  The title of the video – “Phronima: Monsters in Barrels”  Monsters in a barrel? Things are getting interesting!  Here’s a copy of the video on YouTube if you are unable to view it on the original site.

At Plankton Chronicles I learned that the barrel shrimp are very tiny (only about an inch long) and these barrels are actually made of salp which is a jelly plankton.  The description compares the barrel shrimp to the hermit crab but instead of inhabiting larger and larger shells, it finds larger and larger salps to eat and occupy.

Science and the Sea explains it this way:

“The female catches a small, barrel-shaped marine animal called a salp, then uses her mouth and claws to eat the insides and hollow out the ends. She then squeezes inside the gelatinous barrel she created and lays her eggs. As the young hatch, the mother holds on to the barrel and propels the entire brood through the water, bringing fresh food and water to her babies.”

Digging deeper

My search results for barrel shrimp were fairly paltry so this time I searched under the scientific name, phronima.  Much better.  At the top of the list is an article on with excellent photos and a bit of juicy info.  Apparently, the phronima was the inspiration for the chest-bursting xenomorph in the film Alien. Now we’re talking!  That’s the exact kind of trivia and behind-the-scenes info I love to find!

Is it true?

Of course, there is controversy surrounding this claim.  Further reading leads me to believe that the phronima was not actually the inspiration despite the uncanny resemblance.  The design of the alien in Alien was based on a drawing by H. R. Giger.  Click here to see the original artwork entitled Necronom IV.

Where can I see a picture?

A drawing of a male phronima from University of Washington libraries-

drawing of male phronima barrel shrimp
  • Save
[Public domain], via Wikimedia Commons
This is a photograph from the Freshwater and Marine Image Bank at the University of Washington.
Being tiny and translucent, good photographs (in the public domain) of the elusive barrel shrimp are hard to come by.  Check my links to see some good pictures (the best pictures are on Solvin Zankl’s photography sitePlankton Chronicles and  Or you can always just use your imagination.  Despite the fact that the phronima wasn’t actually the inspiration for the alien, there are many similarities.  I’m sure you could come up with quite the picture in your head!


Did you hear that the Smithsonian recently released over 2 million images into the public domain? Awesome!  And thanks to them, I can now add a photo of a barrel shrimp to my story.

underwater photograph of a translucent phronima aka barrel shrimp
  • Save
Thanks to the Smithsonian, I now have open access to this picture of a barrel shrimp to share with you. This particular phronima was photographed floating in the Gulf Stream off the coast of Florida. (You should still go check out those other photo links too to see other even cooler photos of translucent underwater alien-like creatures.)

More about the Plankton Chronicles Project:

The Plankton Chronicles Project is a short documentary series combining art and science, revealing the beauty and diversity of organisms adrift in the currents.

A book has been published with images from the project. You can find it on Amazon. (not at my local library unfortunately but maybe you’ll have better luck) The images on the website are beautiful.

Sharing is caring!

Pin this and spread the word about these interesting creatures.

According to the Super Shark Encyclopedia, the barrel shrimp is a translucent creature that eats the insides of other sea creatures and uses the shell to hold its eggs, pushing it through the ocean depths like a baby carriage. The phronima is also rumored to be the model for the chest-bursting alien in the movie Alien. Is it true?
  • Save
Spread the word – barrel shrimp is not just a dish at Cracker Barrel!!

Follow me for more interesting trivia and stories!

Click the photo below to sign up for my newsletter.  You don’t want to miss out, do you?

behind every day newsletter subscription button
  • Save
Don’t miss a minute! Click the photo to subscribe to Behind Every Day’s fun newsletter!
(You know you want to…)
Websites visited: article with great photos

Plankton Chronicles

Deep Sea Creatures


Wikipedia article about the Alien – extremely detailed origin story and world-building

Wikipedia biography of H. R. Giger

Wikipedia article about phronima

Science and the Sea

Gorgeous photos by Solvin Zankl, a German photographer – definitely worth going to see his photos of the phronima

  • Save

Similar Posts