Not to poke but was there a good reason to drain an entire tank. I hope the fish cures. Is it the red fin strain? I know you probably have it posted up there but I cannot see it right now. Let me know how it does. I think it will survive but may take a while to repair the fin. My suggestion is to never drain an entire tank. I would only do so if there was some dread disease that I had to get rid of and that was the only alternative. How is the SB doing??
No, I didn't explicitly state it, I thought it was obvious from the photo that it's a redfin. The extra salt did not seem to be helping, so I put it in an aerated 5-gallon bucket with 3 tablespoons of salt and some Binox.
The Binox worked on my grass pickerel. When I first brought it home, until I bought a tank for it, I kept it with some darters. Believe it or not, the darters fin-nipped the grass pickerel pretty badly. I did not expect that at all. The pickerels are so mild-mannered, non-aggressive, that when they are small (3") they can be picked on by darters. It didn't stay with the darters for long at all before I bought it a tank, but the darters ate big chunks out of the dorsal, caudal, and pectoral fins. The dorsal and caudal have grown back, but the pecs are still tiny. Anyway, fin rot ensued, and I put Binox in the tank with it, and within a few days the fin rot was gone. That was last October, and the grass pickerel has been fine since. He's big enough now to regard darters as food, indeed, I fed him some Johnny's from a place nearby where I netted scores of them, along with hundreds of juvenile creek chubs. Back then, darters were not food, I fed him guppies mainly.
The growth pattern of the "fungus" on the redfin did not match the growth pattern that the grass pickerel had before, so I did not recognize it as the same problem. But maybe that is because of the nature of the injuries the "fungus" was attacking on the grass pickerel. The redfin had no injuries that I was aware of. However, since they do get paranoid and dart around the tank sometimes, especially when I turn the light on or approach the tank apparently unexpectedly, it may have become vulnerable to fin rot by scraping a rock or the filter intake tube. It's hard to say, but I think the Binox will work.
I understand what you are saying about tank cleanings, but sometimes a tank just needs a good scrub down. And sometimes you need to move a tank. And you can't move it when it's full of water. I moved this one. I have never had a problem doing this before. I feel pretty confident this will work out in the end. I intend to empty out the feeder tank and use it as a hospital tank for a few days until the pickerel is healed.
If, by SB, you mean the shadow bass you sent me, it is doing fine. The spot it had on its side when it arrived, where the scales appeared to be missing, has almost completely filled back in with scales, and its pattern is restored accordingly. I think in a few more days it will be completely filled in. Since you say it was like that when you caught it, there's no telling how it happened, but it's healing quite nicely. It has taken over the hiding spot the warmouth was originally using. The warmouth is now hiding amongst the rocks, and spending more time in the open water. All is well and good for them.