My betta, Oscar, never had any disease until now. 10 days ago he started to show some small black spot on his dorsal fin, and I saw that you have to change the water once a day until it grows back when you notice the finrot after it just started, so I gave it a try.
After that I started using some anti bacterial and anti parasital medicine that I have here. I changed the water 100% once a day and added again the medicine quantity for 5 FULL DAYS, but it DIDNT WORK!
Now im REALLY SAD about him as I have like 100g of aq. salt left in my house, and where I live (Brazil), they dont sell aq. salt (amazing, isnt it?) and, as a rule, all the salt sold in markets as Walmart,etc MUST have iodine.
I will put 1 teaspoon of Aq. salt and change the water 100% everyday until it grows back? How long will that take? I will try to take a picture later and post it so you can see his finrot.
Thanks alot for the help. Is anything else I could try instead of salt? They sell some blue stuff here called marac... (its something like that) and some anti fungal and anti parasital (which I already have but doesnt works).