Ok, i figured I'd chime in since I had one for a few years.
I do not think the OP"s setup will work, there really isnt enough room in half a tank to raise enough pods
for a mandarin. Unless you wait months and months without anyone eating them, then maybe.....but I wouldnt do it myself. I even tried to make a "pod" tank to grow them for a mandatin and that didnt work. :-(
To set the record straight, my mandarin died from excessive stress when I moved him to two different tanks within a week. He was, at the time of his death, eating pellets and anything frozen I threw at him. BUT it took well over a month to get him off of pods
and onto frozen. This involved feeding about 10 times a day over a dozen different frozen foods. My water quality was crap and it was alot of work and attention for this one fish.
In retrospect, I would not try another one, even though mine lived for a couple years, got fat and looked good. As a side note, I purchased a ORA mandarin which was supposed to eat pellets, AND DID NOT! He was only eating pods
when I put him in my tank. I had a small refugium setup which was barely enough pods
to get him thru to eating frozen. I do firmly believe that him being from ORA was what helped me get him to eat prepared, I dont think he would have made it if he was a wild caught one.
My best advice is to really really think about what you want to do. I know it's only a "fish" but to get one and have it die on you isnt' cool. Beautiful fish but a heck of alot of work.