Okay I work in the live fish at Walmart and this sick Betta came in about a week ago. He acted all butt heavy. I fed him a pea and over night he passed waste. He has been perking up but not all the way to par yet. I couldn't just leave him there so I brought him home to see if I could nurse him back to health. I think this Betta has fin rot. He is a red Betta and there is black on the edge of his caudal fin. Is this fin rot? If so will water changes fix this or will I have to medicate?
Here are some pictures. If you look closely you can see the black on his fin. I couldn't get a good picture. His caudal fin is still long and pretty it just looks slightly ragged and black on the end.
Any ideas on what I can do to help this little guy?