Fenbendazole is used as a worming agent in tropical fish. It is extremely effective in both fresh and saltwater environments. Fish do not build a resistance to it. Fenbendazole can be dosed either as a tank treatment or in the fish food itself. It works so quickly almost within an hour!
Recommended dosage is 7.5 mg/gal. Dose once every 7 days for 3 weeks. (1/8th of a teaspoon to mix in fish food)