Mark you are correct. Discus can and do go a very long time not eating before they die. I've seen it happen before. I currently have 2 sibling female discus, at one time you couldn't tell them apart they are marked so similarly. For a few months I'm thinking that one is getting gigantic, but it's the other way around. One is getting smaller and thinner. She schools, she holds her own with the group, she's never off by herself, no indication of internal parasites, her poo is brown, her breathing and her gills are fine. She eats like a bird now, but she is eating some. And when I add live white worms, she'll graze for a couple of hours like the others. One day I know she'll stop eating altogether. She's just not destined to have a real long life.