It seems that activity on this thread has fallen off a bit, and since it is full of so much useful information I thought I would post my recent experience.
A couple of days ago I picked up male yellow belly from Sumatra. I got him for a very good price (even better when I applied a credit I had) from NY Aquatic. I had been in touch with the owner and he advised me that the fish was eating spirulina flakes before he put him up for sale. The owner of NY Aquatic had promised me some spirulina flakes, since I didn't have any, but I was so excited about my new acquisition that I forgot to get them from him. So I stopped at an LFS on my way home and got some OSI Spirulina Flakes.
I am happy to say that he was a beautiful healthy looking specimen, nice and fat. I took about two hours to acclimate him. NY Aquatic had him for just shy of a week, and had him in a tank with copper, 1.017 salinity and a PH of 7.8. Over the two hours I slowly dripped water into a bucket, acclimating him to my tank water parameters of 1.025 and 8.3.
I then put him directly into the tank, skipping a QT period (Not normal procedure). This is a fairly new tank that has been set up for a little over two months ( I have much more experience than that, just a new tank). The only other inhabitants are a female Lammarck Angel and a male lyretail anthias. Once in the tank, the anthias was a little pushy at first but quickly lost interest in the new addition. The Regal took a swim around his new home and went into hiding in the rock.
The next morning I fed the tank, but he really didn't eat much. But he did noticeably react to the addition of some spirulina flakes. Over the next two days he has become much more bold and while not eating allot he has picked at some spirulina flakes, mysis shrimp and formula 1 pellets. I am encouraged that he is at least sampling almost all of the different foods I have tried.