It actually was a sad story on my Sohol tang reefing history.....
She was my 3rd Sohol tang and still not made over 3 months in my tank. The first two were chased hard by yellow tang and always loss on food fighting game. So this time I got the 3rd one much bigger than my fellow tang (I had a rule not spending over US$100 for a single fish, but this one cost me US$130. sigh"¦.), and she was winning over food fight. I though I finally got it, but one day came home after weekend trip, she was gone with only bone left.
I am still struggling on why I seldom lost fish in my tank (well, Anthias may always become less and less"¦), why losing the battle of keeping Sohol tang. Now I suspect my fish food does not have enough algae but that does not explain why my yellow tang grow since last tank for over 3 years. If anyone have a good theory behind, please let me know.