Sorry about the bad luck, but hopefully its just that, bad luck. My first three yellow tangs all dropped dead, 2 before even leaving qt
. I had a trigger that was doing fine, made it through qt
, lived 3 weeks in a well established tank, then stopped swimming one day, wouldnt eat the next, next day he is crab food. Sometimes the fish just dont make it. My suspicion is cyanide poisoning from capture, but thats a guess.
Best suggestion is to pick the hardiest of the fish you want to keep and get him in the tank at least a month. Just be careful he isnt the most agressive too.
I am assuming in all this your ph
is ok. Ph poisoning can kill slowly like that too. PH
, Salinity, Nitrates, ammonia, nitrites....these are your killers when they are off balance. Other things will be bad for corals or promote algae growth, but those things I listed are the things to eyeball.
One last thing. Proberly mixed saltwater with ro
water should have the correct PH
. Dont used additives and chemicals to try to make things "perfect". It will make things worse in the long run.
Best of luck.