if he is not eating or pooping it more then likely is impaction, which will need surgery, more then likely, im surprised because i use to use moss but i stopped because of that reason, i stick with coconut husk now, i had the same problem for a week but he ended up pooping and eating, i wish the best for you and hope everything works out, if he eats or poops he should be good, but the sooner the better i can't see them going past 3 weeks with no food, does he go in his water, and is he pooping? he may just be over weight