I know there's been a bunch of threads about fin rot but I more have questions about it.
Just yesterday I put my male betta Badonkadonk into a brand new five gallon tank (he was in a one gallon with an under gravel filter). I noticed a couple days ago his fins looked more jagged than before and after doing research I found out that it's fin rot. This is my first betta and I'm really scared for him. I am about to run off to Petco before my class to get him something, but what should I get him? I just put him in fresh water but the rips look worse today than yesterday. I saw something about salt? Also I had an ammonia/nitrate remover but because he's never had it before I was concerned to put it in. What did I do wrong and how can I fix it?
Please help :(
EDIT: Is he tailbiting? How would I know?