Origin
Venus was a human named Bonnie, a member of the Punk Frogs, rebuilt by Dr. Barlow as a mutant turtle.
Creation
Venus was created in Teenage Mutant Ninja Turtles #127 by the writer Sophie Campbell and artist Pablo Tunica. The inspiration is obviously the live action female turtle Venus de Milo, who at this point had no comic appearances.
Other Media
Television
Venus de Milo was created by Kevin Eastman and Haim Saban for the Ninja Turtles: The Next Mutation live-action television series (1997-1998) as a fifth mutant ninja turtle.
Venus was the fifth turtle created by Splinter, she also mutated but was lost by Splinter, she was found by Chung I in Chinatown and taken to China by Chung I, who named her Mei Pieh Chi, who taught her the ninja arts, she returned to New York and joined the team.
She appears in the crossover with the Power Rangers in the episode Shell Shocked (February 1998).