I am sorry to hear this. You tried your best to keep it alive but it is an extremely difficult fish to keep. Please do not replace the Powder Blue with another.

You should be treating the fish in your tank because they will have ich and will also be stressed.
Soak your food (preferably dry food because it absorbs more) with garlic extreme or garlic extract and selcon. Feed very often and do this for several weeks.

I think the worst experience I ever had with a fish was the powder blue.

Beautiful fish.

I must have gotten lucky. Come late April, I will have had my Powder Blue for 4 years. It has survived the the intial move from the store to the 135 I used to have, and two other tank transfers...the second of which involved a 20 minute car ride in December '06. I've seen a few spots of ich on it only twice, and that was in the early going. The only thing that frustrated me about it was it used to splash at the surface. But I solved that by putting a partial glass top on the tank. I take your guys word for it that they are difficult. Mine is a success story. Lucky, I guess.

Cheers,

I think it comes down to tank size and mates. I've had little trouble with keeping PBT, they're just as easy as a Yellow tang if provided with the right environment.