Starving mandarin despite pods?

[Kal93]

2 days ago, I purchased a healthy, fat male mandarin (~3" long). He has been picking away at my rockwork, but today I noticed that his belly looked significantly shrunken compared to when I purchased him. I don't understand--my refugium and glass is crawling with pods! How could this happen in 2 days? I tried feeding him calanus and can'o'cyclops, but he didn't eat it. I was thinking of getting some flying fish roe to try next, or finding another owner. Any advice?

 

[ChiSox Rabbitfish]

Must be something else wrong fish don’t starve and start looking skinny in 2 days a fish can go days without eating before starvation starts becoming a real problem

 

[Bleigh]

Do you have a picture of his belly? And perhaps a picture where he was big and fat?