I agree that it is best to keep the stress as low as possible. However.... Given how lethal and strong this disease is, this fish needs strength. And yes fish can go a very long time without food, however it does take a toll on them especially in CB fish that are fed regimentally and haven't had to survive like that, I think if he doesn't for a week then you should force feed because his immune system must be fueled, it isn't just the meds that are doing are the work. If people are sick and can't eat, we get an IV because it is necessary to keep the immune system healthy while it is fighting. I think if you do force feed him, don't mush regular food. Add vitamin supplements, and make almost a SUPER food, load it with vitamins and minerals as well as protein. So yes, he can go a long time, but that is without a illness, especially not a illness like this. This is the time he needs to be able to fight the strongest, he will have much less chances of getting through this if his immune system is not kept in check.