Thanks guys. Ok I will try turning the lights off for today. Unfortunately the DT is in a well lit room so he will get some natural light in there but at least it won't be coming from the LEDs.

I was told once that a water change can stimulate appetite. Also, make sure there is not stray voltage with the new powerheads. Hope he comes around, good luck

Ok I just got home from work and sailfin tang is still hiding but now he is bloated looking and the cleaner shrimp were on him. This is the first time I have seen him allowing the cleaner shrimp to clean him.

Keep an eye on him if I Were.

When was the last time you add new livestock, especially new fish? Bloated fish doesn't usually live long, IME. Try to treat it in a QT with antibiotics, pronto. I am 0:2 on bloated fish. Maybe they are too far gone when you notice the unusual body shape.

Tang was dead when I got home from work.

Other fish still seem fine for now... I hope they stay that way. The last thing that I need right now is a crash or to lose my precious CBB.

Oh crap. Sorry to hear this.
'fingers crossed' on the rest of them