Got my cooperband butterfly fish eating after 26days!!!!!

Just when I was losing hope and thought it would stave to death, tonight my cooperband accepted mysis shrimp.
– yet oddly NEVER eat the crab meat – muscles – malina clams (one a day) scallops I kept offering every day. That was one stressful fish to get eating. I’m just so happy he eat today…he has been in a 30g in the basement for the last week with 50lbs of live rock (covered in majanoes) since he wasn’t eating in my main tank I thought maybe he might pick at those majanos…
I wonder how long till I can move him back to my 90g…leave him in the 30g and keep feeding him for another week before putting him back in main tank?