Hi, I recently tried keeping my first Mandarin Fish. I had plenty of tiny creatures in my sump, assumed to be copopods, and added corals on live rocks weekly to keep the copopod population high. Initially, I thought he would adapt to my aquarium well, he regularly nibbled at rocks and substrate. After a few weeks, he went missing for a few days, and when I located him he was terribly skinny and weak. He died. Do you have advice on keeping Mandarins? Would cultivation and addition of phytoplankton ...