The Dopefish is a fictional fish that originated in the fourth Commander Keen video game, Secret of the Oracle, released in 1991. The character has since evolved into a PC game industry in-joke, making appearances in games from Apogee's 1994 Wacky Wheels as well as titles as recent as the 2006 SiN Episodes: Emergence and 2007 Chili Con Carnage and more recently including 2011's Deus Ex: Human Revolution and 2012 Natural Selection 2.
Physically, the Dopefish is a large green fish, with buck teeth. It is described in Keen 4 as "the second-dumbest creature in the universe" (a reference to the Ravenous Bugblatter Beast of Traal from The Hitchhiker's Guide to the Galaxy, the dumbest) with thought patterns that go "swim swim hungry, swim swim hungry". The game also mentioned that they would "eat anything alive and moving near them, though they prefer heroes". Whenever it does eat something, it turns to face the viewer and belches. id Software's Tom Hall later gave it its fake scientific name: Pisces swimeatus.
In October 1995, Joe Siegler of 3D Realms launched the Dopefish.com web site as an archive of all things Dopefish-related. Siegler reportedly maintained dopefish.com on company time while working for 3D Realms. Since launching, the site has inspired a variety of artwork and merchandise based on the character., including ASCII art, stuffed toys, and mugs.
Tom Hall first conceived of the Dopefish as one of 24 potential characters for Keen 4. In his words, "I just drew this stupid little fish". In the game, the Dopefish appears in one level, The Well of Wishes. In this level, the player must avoid being eaten by the Dopefish, along with other hazards, in an attempt to rescue a Council Member. The music for the level, titled Eat Your Veggies and originally composed by Bobby Prince for use in Keen Dreams, is also commonly associated with the Dopefish and has inspired some spin-offs compositions including Fish Polka and Dope Jaws by former 3D Realms Music and Sound Director Lee Jackson.