Fenbendazole is toxic in the water, it should only be used in food. The one that can safely be used in the water is Flubendazole. If the fishes are still eating, treatment is more effective when administered with food. However, the food must be eaten quickly, or else the medication will dissipate in the water, so treating algae eaters with food might be more difficult. Since you have fenbendazole on hand, I would try that one first in the food. Meanwhile, you could order some levamisole online so that you can treat the water in case you can't get the fishes to eat the fenbendazole.
When I treated my fish for capillaria (treatment is the same for camallanus), I thawed frozen bloodworms in the fridge and added 2,5 mg of Fenbendazole / gram of food. Then I used Knox unflavored gelatin to bind the medication to the bloodworms. Make sure to calculate the dosing based on how much Fenbendazole your medication contains. For example, I used Fish Bendazole. One packet contained 250 mg of Fenbendazole, but actually weighed 2000 mg. So to dose 2,5 mg of Fenbendazole / gram of food I had to add 20 mg of the Fish Bendazole / gram of food. I fed this medicated food for three consecutive days weekly for three weeks. You can repeat for three more days three weeks later just to make sure all the larvae are dead, but it might not be necessary. Some of these worms have developped resistance to certain medication, so if you don't see any improvement after two weeks, I would try a different medication.
When I treated my fish for capillaria (treatment is the same for camallanus), I thawed frozen bloodworms in the fridge and added 2,5 mg of Fenbendazole / gram of food. Then I used Knox unflavored gelatin to bind the medication to the bloodworms. Make sure to calculate the dosing based on how much Fenbendazole your medication contains. For example, I used Fish Bendazole. One packet contained 250 mg of Fenbendazole, but actually weighed 2000 mg. So to dose 2,5 mg of Fenbendazole / gram of food I had to add 20 mg of the Fish Bendazole / gram of food. I fed this medicated food for three consecutive days weekly for three weeks. You can repeat for three more days three weeks later just to make sure all the larvae are dead, but it might not be necessary. Some of these worms have developped resistance to certain medication, so if you don't see any improvement after two weeks, I would try a different medication.
