sick hippo

[tnr]

I bought three hippo tangs last week.Put them in a 40 gal qt.
All have been doing great ammonia little high.Till tonite change 10 gal of water and ammonia jumped up.2 of them are doing great but on is breathing real heavy color is fading and has no clue what its doing.Anything I can do?Have a strong feeling he'll be dead by morning.
Sorry about posting twice.

 

[tnr]

as stated i use a 40 gal quarintine tank. This is not my first tang have a pbt for over two years. and had other tangs.I never had this problem before.Just looking for a little help. You act as if im an idiot thanks for the help.Now I remember Why i left this board for a while.