This is the third time that my fish got the infections. I followed the directions changed the h2o 25% after every dose but my fish still has the crystals on him and it looks like he is spreading to other fish. VERY FRUSTRATING!!!! Can anyone help!!
Have you tried putting your most infected fish in a separate tank for now? What kind of fish do you have? You could try raising the temperature of your tank to help prevent ich from multiplying (maybe like 78 to 80 degrees). Also, some aquarium salt tould be great for your fish to help aid in the medication and soothe your fish.
It could be from either over feeding or just general stress amoung your fish that causes these infections. I would just keep with the medication, raise the aquarium temperature, and do the daily water changes.