120gal mixed predatory reef tank

[asylumdown]

I suspect something had been going on with that CBB for a while as he was very underweight. You can see how he the curve of his body below and behind the gill flap and above his eyes are concave, so he had probably been wasting for a while, likely so slowly you didn't notice. He might have had gut parasites, or some other conditions that made it hard for him to absorb his food.

In any case I'm sorry you lost him. I had mine for a year when he mysteriously died of what I can only describe of the fish equivalent of lung cancer. An entire gill was replaced by some sort of tumour over the course of weeks, then one morning he was just dead, after behaving perfectly normally the night before. They're fickle animals.