Brasilliensis tail detiorating to nothing....

[we4wieners]

I have a 180g south American tank with severums, daemons, uarus, Tapajos, heckelli, loaches, cories. Have never had any health issues in many years in this tank. I noticed my brasilliensis at the top and its when I first noticed his tail showing signs of stress. I also have a Bala that is constatntly nipping at his detiorating fins. Here is a series of pics within a month period. first pic is after adding him to a 10g hospital tank. Daily water changes and Fungus Cure has brought him to the last pic. Could this be an injury???

 

[we4wieners]

Any ideas?

 

[Charney]

i worry about aggressive bacterial infection. I have actually had good luck with MB with fin rot with some of my fish in the past.

 

[altumangel]

R.I.P brasi

 

[duanes]

Just a possibility.
Most of the other tank mates are equatorial species (warm water species), but the braziliensis come from southern Brazil, Uruguay, and Argentina is a much cooler water species. You don't mention temp, but if you have the tank a constant 80+'F, this may be a factor, as the metabolism of cooler water species will be on overdrive, and certain bacterial species that equatorial fish have innate immunity to, the braziliensus may not.
I usually kept species of the braziliensus complex in room temp tanks, low 70s, even high 60s. Mine have even spawned around 68'F in outdoor tanks in Wi.
A heckelli are from 3000 miles north of braziliensus, in S America, south means cooler.