Need help treating bacterial infection

[Jay Hemdal Verified Community Expert]

@Jay Hemdal, do you know if Edward J. Noga is still around and accepting submissions of samples? I tried to find a contact address or e-mail but he is not listed at the directory of the NCSU College of Veterinary Medicine that he gives as contact in his book.

Sorry - I've never met him. I know a number of the "old guard" are close to, or are retired; Carlson, Moe, Gratzek, Spotte...

Ha! I found him on Facebook - we have 23 mutual friends (grin). https://www.facebook.com/edward.j.noga

Jay

 

[ThRoewer]

As I had feared, I found her dead when I came home.:(

 

[ThRoewer]

So, when the first 2 died I got another one and it seemed to be fine. It started eating right away and by last week even took flakes.
It had a little cloudy pectoral fins but no significant fin damage. Yesterday evening I took a closer look and the lef fin looked like covered in mucus and I decided to treat the tank with neoplex. When I came home this evening the water was cloudy. So I did a full water change which got the Betta out of its cave and allowed me to take a closer look at it. What I saw was not good - the fish has light skin patches like the others and its left fin base is bloody. It looks like it has the same as the others.
The store where I got them all runs low dose copper and furan in their fish systems and it seems that this had helped as this one looked initially worse than the others - the reason why I didn't get it with the first lot.
So I'm wondering now what this could be if low dose copper and furan help. Furthermore I wonder if I should pull the fish out off its current quarantine tank and set up another qt for copper/furan treatment (current qt has live rock).
What worries me is that in a new sterile tank things may get worse and the fish may stop eating. I'm also not a great fan of copper or treating blindly without knowing what I'm actually up against.
So anyone having an idea what this might be?

 

[ThRoewer]

This video was taken a few days ago when there was just barely noticeable cloudiness on the fin:




For now, I treated the tank with Furan. Let's see if that does something. If I don't see improvement I need to come up with something else. At least the fish is still eating.

 

[ThRoewer]

Two doses of Furan 2 in and the white cloudiness on the fin has disappeared. But now the edge of the fin looks like melted plastic and is pigmented black where it should rather be clear.
The real problem is the basis of the fin which is a white or bloody sore all over. That is the part that concerns me the most right now.
I'm also not sure if the fish is still eating.
I'm wondering if I should continue wit Furan or, considering that this might be vibrio, switch to Cipro.
@Jay Hemdal, any suggestions?
Given that this fis was doing good and eating for over 2 week, this is particularly disheartening.
The Assessors (a closely related species) show so far nothing and the bicinctus are fine.