A "red herring" is a piece of information which is used to distract a questioner from the real topic. Or a false clue designed to lead you astray. "People protested about the chemical factory polluting their town, but the mayor gave them a red herring by talking about a new school." "The murderer left a red herring at the scene of the crime - a handkerchief belonging to an innocent man."

a piece of information or suggestion introduced to draw attention away from the real facts of a situation. http://idioms.thefreedictionary.com/red+herring

Thank you, Richard, It's very interesting.

The origins of many English terms (Etymology) can be found on the following website: http://www.etymonline.com/ Herrings are fish. Red Herring mean: "smoked herring" early 15th century (they turn red when cured/smoked), as opposed to white herring "fresh herring." Supposedly used by fugitives to put bloodhounds off their scent (1680s), hence metaphoric sense (1884) of "something used to divert attention from the basic issue."