so after a couple months of frustration and testing, I finally found out what the culprit was. Regrettably it took a couple more fish dying before I realized that I had a very serious bacteria outbreak in my tank. I put another foxface in after I had gotten rid of the damsel. Regrettably he dies a very slow and painful death. However, his sacrifice was not in vain. He showed a puffed belly and ashen scales(dropsy), the initial signs of popeye, and fin rot. All apparently (according to people I've spoken to so far) signs of bacterial infection.

As such, I began treating with melafix and pimafix (per APIs recommendations). Regrettably, even they admit that this can accelerate some forms of bacteria while killing others. This treatment killed both of my firefish, and appears to have pushed my goby over the edge. He's laying in my quarantine tank looking worse each hour, and he shows signs of fin rot. I'm hopeful, but anticipating that I'll lose him by tomorrow.

On the plus side, most of my invertebrates appear to have made it thus far, so that will be good at least. I have moved everyone over to the quarantine tank, drained and refilled my display tank, added a protein skimmer (yup, I tried going this long without one - I know, I know...:( ), and a UV sterilizer. I went with the Coralife 6x 18w. It appears to have mixed ratings, but we'll see how it goes. Thank ya'll for all the information you've given me so far. I haven't posted in a while, but I keep reading regularly.

Thanks,
Aaron