Well, it's been four days since your 7/6/06 posting. You probably have though of this but be sure to rull out that low DO is not the cause of high respiration. As you may know, DO reduces with increasing water temp. I just thought of this as you did not report any observation of "spots" or other evidence of parasites.
Also, you can try a 5-day dose of Mynacin (or equiv drug treatments found at Petco, etc). My sick blue tang started easting immediately upon starting such a antibiotic treatment. This is usually recommend to control secondary infections, in addition to copper for parasite.
When I did this, I was greatful for the "disease guide" that came inside the Mynacin box .... was very helpful.
Also, don't forget to watch ammonia spike in your qt .... handy to use Ammo Lock to convert this rising ammonia to less toxic form of ammonia to tide you over between water changes, etc. in your qt.
Hoping you didn't lose the little fella. Best of luck.
