Fish Fen is 99.25% pure fenbendazole powder for fish. It has been third party independently lab tested to insure quality. Fenbendazole is difficult to dissolve in fishtanks so we have included DMSO as a solvent. For a 50 gallon tank dissolve 1/8 tsp (300 mg) in 5-10 drops of DMSO before adding to your tank.
Fish Fen is a supportive agent designed to remove worms and other parasites from fresh and saltwater aquariums and from within the fish themselves.