I got a Heniochus Butterfly 2 days ago.
I noticed my ammonia rose just a little bit, from 0 to 0.25 so I added Nitromax Marine.
The fish was breathing heavily and swimming in circles about 3 hours after I added Nitromax, then 4 hours later he was dead.
Before I added Nitromax that fish was eating and swimming around just fine. All the other fish are doing great. He had been in the tank for about 36 hours before I added Nitromax.
Or could this have been a bad fish from the LFS