Well on Tuesday afternoon I took Monet out of his 2.5 gal tank and put him in a hospital tank along with one of his silk plants, his live Anubia Coin, and his heater. By that afternoon he was more interested in food then he had been for quite awhile. The next morning he was doing a bit better and he ate well, honestly it's the best I had seen him doing for probably a month. Later that morning he scared the heck out of me by being on the bottom of his tank bent double like the letter n. What the.... I think the might have been looking for dropped food, or preparing to attack his tail which he did a short time later.
In the meantime his new gravel arrived. I stripped his tank, threw out all the old gravel, cleaned the tank with vinegar and rinsed it well. Rinsed everything in it in hot water, cleaned the filter with vinegar, and rinsed the filter sponges in clean, treated, water. Then put the whole thing back together minus one of the silk plants. I let the filter run for an hour, put the heater back in and let it calibrate for an hour, then let the whole thing run for another hour before putting Monet back in.
Today Monet is more active then I've seen him in months, he's swimming around checking everything out, laying in his plant, inspecting the gravel, he actually went after his food this morning.
It's making sense though. He'd seem to be doing a little better after a water change despite the levels always being good. I was taking the toxic water out, replacing it with fresh water, only to have the toxins build back up within a day or two. Those water changes likely saved his life. It's also probably why the PraziPro seemed to work at first, I followed the directions and did a large 75% water change before using it. Now I just wonder if whatever chemical in the gravel was causing the problem did lasting damage
Oh he's definitely tail biting and I'm not sure if he's marbling or his blue color loss is from something else...
Here's some pictures. The first is his old tank set-up, second is new tank set-up, third is how he used to look, and forth how he looks today.