Hi there!:wave:
I'm sorry to hear that you're having a problem with your flame angel; even though they are quite hardy they're still very sensitive. I know what you're going through; I had the same trouble with flame angels, coral beauties, bicolor angels and emperor angels when I was younger.
Try not to think about what the shippers did wrong and start thinking about what you might have done wrong. How big is your QT tank? What are its water conditions? What's in it besides the angel? is there a sand bed and plenty of rock? Could you change what you're feeding it? Is there anything else you can alter to make the angel more comfortable? Did you read up on flame angel care? Did you properly treat your QT tank in between sessions? How did you treat your tank water? Most importantly, what is the copper level in the water? Copper is the kill-all angelfish destroyer.
Remember that the quarantine process is not always a good idea. The smaller, cramped conditions, not to mention the constant acclimation and medications, can be detrimental and almost fatal to the fish in question. Unless you do it right, you might be killing the fish. Sure, cyanide might be to blame, but so could your own aquarium conditions, especially considering that multiple specimens of Centropyge loriculahave died under your care. Do everything you can to make the angelfish more comfortable, and you'll have a radiant red, black and blue flame angel brightening up your tank in no time.
Keep up the good work!
-BlueDolphin123:fish1::fish2: