Thanks,Hi Mike, Sorry you’re going through this. I appreciate some of the varied possible problems and solutions on this post. Thinking outside the box has sometimes produced results. Here’s one that hasn’t been touched on as yet. Do you periodically have home maintenance people: maids, bugs guys, interior home construction, wife, kids, you etc. spraying toxic chemicals around or near the tank? Quick example: A family had a home, a 45 or so gallon tank. Two 7+ years old large Percula clowns. Their new English Sheepdog puppy decided to use the rug in the aquarium room as a toilet. The owners got a cleaning crew in to both clean up the rug and spray the room. The very next day the two clowns were dead. They had a skimmer on their tank which I’m sure accelerated the problem, bringing more toxic air into the tank. Fish and corals are in my experience pretty tough, resilient creatures but in a small confined glass box we have to be careful of the air that they breathe or what lands on the water’s surface. Again consider everything that is being sprayed around your tank. Good luck.
This was a concern from the beginning, and I have honestly racked my brains trying to think of anything that could be a factor. Before I even set up my tank I'd watch every BRS TV beginner video going and one of those talked about how aerosols were a big no no so I made sure to let my wife know in case there was a big wasp or something and she got the fly killer out. But even spray polishes we replaced with tinned wax for this very reason.