One example of a red herring fallacy is when two people are discussing the benefits and drawbacks of voting to increase the minimum wage, and one person changes the subject to removing tax breaks for wealthy people. The second topic is only superficially related to the original topic at hand.
A "red herring" is the name for a logical fallacy intended to draw attention away from the issue being discussed and toward a separate issue that is only minimally related to the original issue. The red herring fallacy is often cited during political debates; candidates arguing with one another may bring up new hot-button topics to distract the audience from the matter being discussed. During such debates, one red herring may be countered with another, with both candidates attempting to deflect from the issue at hand.
There are many theories about the etymology of the term "red herring." When smoked and cut apart, the meat of a herring takes on a ruddy hue. Smoked herrings were popular for use by hunters in the past, as the pungent smell of the fish could serve to train hunting dogs to follow an olfactory trail. Brigands were also said to have carried smelly herrings on their person when running from the police, who typically pursued criminals with bloodhounds in tow to better their chances of capturing them.