Pheromones play important roles in the life history of fishes.Their functions can be classified as alarm,social organization and reproduction.Disturbance pheromone and alarm pheromone reliably allow conspecifics to assess predation risk and escape from predators.The putative ostariophysan alarm pheromones are purine-or pterin-like substances.Bile acids may function as the primary pheromone components of individual recognition,kin selection and migration in fishes.Most teleost fishes employ discharged sex hormones and their metabolites as pheromone to synchronize reproduction between fish while male sea lampreys(Petromyzon marinus) use bile acids to attract females.