Fish lice (Argulus), anchor worm (Lernea), gill maggots (Ergasilus) are just some of the horrific parasites/ predators which can attack fish and are almost invisible to the naked eye.  Parazin P destroys these and other insect and crustacean parasites/ predators found in garden ponds.  This is a unique and revolutionary product that usually only requires one dose per infestation.