An illustration depicting the anatomy of the fictional babel fish based off of stories from The Hitchhiker's Guide to the Galaxy, which is a comedy science fiction television series created by Douglas Adams. Originally a radio comedy broadcast on BBC Radio 4 in 1978, later it was adapted to other formats, and over several years it gradually became an international multi-media phenomenon. The Hitchhiker's Guide to the Galaxy was also made into a film in 2005 starring Martin Freeman.
From The Hitchhiker's Guide to the Galaxy:
"The Babel fish is small, yellow, leech-like, and probably the oddest thing in the universe. It feeds on brain wave energy, absorbing all unconscious frequencies and then excreting telepathically a matrix formed from the conscious frequencies and nerve signals picked up from the speech centres of the brain, the practical upshot of which is that if you stick one in your ear, you can instantly understand anything said to you in any form of language: the speech you hear decodes the brain wave matrix."
Below is a monochrome version and a color version. The color version is availble as a poster on Society6 @Viettriet. Buy your own today!
Below are sketches of the fish before the final artwork.
Below are video clips from various adaptions of The Hitchhiker's Guide to the Galaxy presenting the Babel Fish: