Am I Making Progress?

I hope I've put this in the right forum. I have been dealing with this for going on about 8 weeks. I have 2 green barbs in quarantine (there had been a 3rd that died Thursday) for about 3 weeks now. It started out as nipped tails...nothing too severe, but the nipper was rehomed and I watched the injured barbs closely to make sure there were no other nippers and to see new growth appear. Neither happened. No new growth but the tails didn't get worse either. I kept up with water changes and testing and everything was in order. About 3 weeks ago I noticed that the now frayed tails we're getting a milky look to them so I removed them to a 10 gallon hospital/quarantine tank. I put a well used sponge filter in and did daily water changes for about 10 days. Got no improvement and around the 2 week mark noticed the tails we're developing white fuzz. So I added aquarium salts to my routine and Paraguard along with Melafix. Three days of this and only more fuzz and now the tails were beginning to look red. I researched and came up with Calumnaris as my diagnosis...so ordered Kanaplex and Furan 2 from Amazon. The casualty happened the morning I received the meds. Anyway, I used qtips to gently wipe off the fuzz of the remaining 2 and dosed the tank with both meds. I've been doing the Furan 2 daily and the Kanaplex every other day. Water changes the day I started and yesterday. I'm finishing the first round today and the fuzz is back but not as bad as before the treatment. It actually looks like it's trying to roll off in one piece on the barb that seems more severe and the redness at the tail seems to be healing over. I want to say that's improvement but I was very disappointed when the fuzz came back after 3 days of treatment. Maybe it's one of those things that gets worse before it gets better? I'll attach pics I took today. They get the last dose of Furan this afternoon to finish the first round.
Am I making progress or is this a lost cause because itsI so advanced? I don't want them to suffer anymore if there's no hope. They haven't eaten anything for about a week. I've tried the garlic juice and blood worms.
The tank parameters for the tank they came from have been very stable for months. Tank was started last December. I have 10 ppm nitrates in my well water so they are consistently between 20-40 (never actually 40 but somewhere between the two) before and after water changes. 0 for ammonia and nitrites. Temp is between 78 and 80 without a heater. It's 75 gallon, has a Sunsun 404B canister with a AP Solutions filter booster, Marineland Penguin 200, and 2 sponge filters. I do about 30-50% water changes and gravel vac every Sunday.
I've got to run out for a few hours but hope to get some feedback in the meantime. Is this a lost cause? I feel like such a dirtbag for letting them get this bad...

 

If it was Calumaris I feel the fish would of died by now. My guess is the nipping lead to infection and then that infection led to body rot. You should switch to something more heavy duty as melafix isn't going to cut it. Sounds to me you are on the right track with the kanaplex and Furan2, it will take some time for it to show if things will work or not.

 

OK, thanks for the reply. I figured if it wasn't calumnaris then it was a bacterial something and the treatment should work for that as well. I added salt to the tank yesterday with the antibiotics because the two are staying at the top of the tank now. I have a 5" air stone in there but it seemed to be pushing them around too much so I turned it off. I sure hope they eat something in the next day or two. I just got home and the fuzz does seem to be peeling back off the tail now. And the actual tail seems a little more healed and a little less red than this morning. Maybe they can survive this. Fingers crossed...And lots of antibiotics!

 

Update...the treatment seems to be working. The white fuzz basically peeled off in almost one piece for the one that seemed the worst. His tail now looks much cleaner and the redness of the tail looks less raw, like it IS healing. And they both ate some frozen blood worms today. I'm feeling hopeful they're going to pull through.

 

I started the 2nd round of Furan 2 today. The two barbs are definitely improving. Tails are still red right where the fin comes out, but less so than before and all the fuzz has gone. One of them has developed what looks like an ulcer near a pec fin and one red dot further up on his tail. I've added another barb to the qt whose tail tip had been nipped and just didn't seem to be regrowing. Since I'm only doing the Furan this round I thought I would give him the extra boost to stop any possibile issue that might arise. The trouble maker who caused all this has been gone for about 2 months now!
Anyway, I was wondering if I should add Melafix to the tank or not? Does it actually help the healing process?