I want to give a shutout to
@Humblefish for his recommendations. I moved the group to an observation tank 8/9 days ago and lost another female. After the female went, the male started showing the dreaded lethargic behavior. I administered a 150ppm H202 bath for 30 minutes and moved them to the display tank. It took nearly a week, but the male slowly turned around.
At first, he just sat on the sand bed. Then the next few days he started swimming up to the corner of the tank, then back down. Then stayed up at the corner of the tank. Finally, within the last two days, he seems back to full health, swimming about in the water column.
I don't know much it had to do with it, but my Naso tang kept a close eye on him, and kept doing something that I could only describe as, "Hey buddy, come swim this way." Almost as if she was constantly encouraging him. Absolutely amazing to watch.
I've also setup a doser to feed periodically throughout the day. These are my pets, and spare no expense for thier health.
Now that I know it works, time to put it inside a refrigerator.
Thanks again
@Humblefish!!!