I also have problems with tangs. I have in my tank right now and doing great a hippo and a kole but I have had in the past 2 convict tangs, 2 mimic yellow tangs, 1 ebili mimic tang. I also don't know what is going on. Everything tests out ok. But yet don't know what to do. I would like to have one more tang in my tank but don't know what to get. Of those 5 mentions the convicts lasted the longest. I loved them!