red herring

Believe it or not, red herring has as much to do with hunting dogs as with brightly colored fish. Here's how: A herring is a soft-finned bony fish. People who like to eat herring have long preserved them by salting and slowly smoking them. That process makes a herring turn red or dark brown - and gives them a very strong smell. Dogs love to sniff such smelly treats, a fact that makes the fish a perfect diversion for anyone trying to distract hunting dogs from the trail of their quarry. The practice of using preserved fish to confuse hunting dogs led to the use of the term red herring for anything that diverts attention from the issue at hand.