I agree, When I first got my mandarin I gave him up because he was not happy but he was eating prepared foods and eating Rods Food out of my hands, since giving him up I wanted another Mandarin but I waited until my POD population grew- Once I knew my tank was ready I Purchased a Red Mandarin which I loved and he was a little guy started eating Pods
like crazy but my system was infested with PODs
he didn't have to worry about it deminishing quickly. In the end he was Fat and Healthy and started to even eat prepared foods which was good becasue it was an extra food source. I don't have him anymore becasue I had to break down my tank but he is in a happier and bigger tank.
If I where you I would wait until you have a huge POD population and maybe some more LR
to add to your 55G at least another 60LBS worth if you want to keep one. JMO