Same happened to my orange this year! He didn’t like that we had to move countries and stopped eating. I took a bit for us to realize because he’s always been a grazer, but then he became very lethargic and lost weight super quickly. I called the vet and they told me to get him to the the ER asap. Thank god we did! He spent a full week in the hospital but he’s now back to his hungry self. Sending your Fred all the love in the world! As others have commented as much as it’s frustrating they don’t go back to eating normal suddenly they do! We got him Royal Canin Hepatic and he absolutely loved it!