Parazin Parasiticide Fish lice Argulus anchor worm Lernea gill maggots Ergasilus are just some of the horrific parasitespredators which can attack fish and are almost invisible to the naked eye. New Parazin destroys these and other insect and crustacean parasitespredators found in aquaria. This is a unique and revolutionary product that usually only requires one dose per infestation. For use in tropical freshwater and coldwater aquaria.