This is a discussion on help!!!! within the Saltwater Fish Diseases forums, part of the Saltwater Fish and Coral Reef Tanks category; -->
For some reason my chemicals has changed.
I test the water on weekly basis. I did a 10% water change last week. I feed ...
Your ammonia is the one I'd be most concerned with. Small frequent water changes to remove it physically, over skim (turn it up wet and dump it daily), stop feeding or feed lighter, possibly add some Purigen from Seachem. Your natural biological filtration should be able to recover and handle the amonia problem once you figure out what is causing it. I'd say either something unkown to you died or that you are feeding to much at each feeding.