Hello, I am at a loss of what to do. I've had the guy for well over 5 years and he has always been healthy up until recently. I first noticed that he stopped eating and had some sores on his mouth along with his eyes being sunken in. That's when I moved him into an isolation tank. I proceeded to treat him with API fin and body cure along with Primafix. I did the full treatment regimen and saw a small recovery with his eyes returning to normal. However, he still won't eat and those sores have spread and are worse. Please Help! He has been in a 125-gallon tank and all my water parameters are within spec. Please see attached photos.