I have had my fish for 5 months. He lives in a 1.6 gallon tank with a filter. It is currently 78 degrees and ammonia is at 0. Unknown pH... I treat the tap water to remove metals, chlorine, and chloramine. I occasionally use amquel to remove ammonia and nitrites. I use aquarium salt whenever I do complete water changes (weekly). He has had some mild-moderate tail rot in the past treated with water changes or antibiotics.
My fish has a single white spot on his mouth. It is small and doesn't appear fuzzy. He is lethargic and hasn't really eaten in 5 days. I treated with 4 days (suggested course) of E.M. erythromycin (antibiotic), which I have not used before. His condition did not appear to improve, so i decided to try rid-ich plus for 3 days. Again, his condition didn't appear to improve and I now doubt that he has ich since he only has a single white spot. I did a complete water change today and am not sure what to do now. Any suggestions for treatment or cause of the white spot? Sorry for the lack of picture, but it is small, very white, has not grown, and does appear cottony