Dorthy-Dan my Halfmoon male beta fish
My betta fish which I got a month ago has this cotton ball like thing in his fin. He is constantly lying around in his hammock or hiding behind rocks. He won’t eat at all either. We have done a treatment where we take the betta out in a separate tank and bake the substrate and bleach everything else. It worked for about a day then it came back. It’s been four days since he last ate and I have no idea what to do. PLEASE HELP!! Thank you!!