I had a green mandarin setup to train prepared foods. It was in an acrylic box that hung off the tank & allowed water to flow through from the tank. This kept him isolated and allowed easy target feeding.
Within 2 days it was eating garlic soaked frozen brine and a few days after he was eating garlic soaked Reef Pearls. He grew like mad for the 1.5 weeks he was in there. Unfortunately a hardware malfunction caused his death before I could transfer him.
I would only put a mandarin into my tank after training. Even if you feel you have the pods
, this way you can be fairly sure you have a backup to keep it alive. You can't train them effectively in tank.