Complex sentence: The Babel fish is a fictional species of fish in "The Hitchhiker's Guide to the Galaxy" series by Douglas Adams, that can instantly translate any language to any other language, and is the source of AltaVista's web translation service's name.
Split into simpler sentences: The Babel fish is a fictional character in "The Hitchhiker's Guide to the Galaxy" series by Douglas Adams. It is introduced as a species of fish that can instantly translate any language to any other language, and is the source of AltaVista's web translation service's name.