Mystery illness going through tank

[Plutoids Mom]

When to pull healthy fish from quarantine? - Diseases - C.A.R.E. (aquariumcoop.com)

As a depressing continuation from the other thread, something is going through my 75 gallon.

Tank's history:

• Has been setup and running for almost 6 years.
• Added last fish 3 months ago.
• In March, swapped out the Fluval 405 for a Seachem 75 because my angle fish liked to sleep under the intake and it was really hard to maintain. I let the new filter run for two weeks in the tank before I turned off the Fluval.
• First fish, pearl gourami, died on April 4. Had mystery lump on one side for about a month that got bigger or smaller depending on the day.
• Five fish, gold barbs, became sick, swimming nose down, on April 8 and last of those died off on April 20.  Were in a quarantine tank the whole time. Treated with Kanaplex and then Maracyn.
• Rosy barb started swimming in circles and slightly U shaped spine yesterday, April 22. Moved to quarantine tank and added salt.  In really bad shape, so decided to not use existing meds in case I need them for main tank.
• Added salt to the main tank at 1 tablespoon to 2 gallons last night.
• One black skirt tetra is having trouble swimming upwards this morning, but still eats with relish.

Current occupants as of this morning:

• 1 pearl gourami
• 1 gold barb
• 1 angel fish
• 6 skirt tetras
• 6 congo tetras
• no plants or invertebrates 

Parameters:

• Ph 8.2
• Ammonia 0
• Nitrites 0
• Nitrates 10
• Temp 76
• Do weekly 25% water changes with 3/4 water from residential water softer, 1/4 well water.

Since Kanaplex and Maracyn didn't make a dent in the gold barbs that died, should I even treat the whole 75 gallon with meds?  Keep pulling the sick fish into the quarantine tank?  Wait and watch my invisible train wreck of a tank?

 

[Colu]

Have you treated for parasites 

[Plutoids Mom]

No, I haven't.  Just bacterial meds.  Paracleanse is the recommended med?  And the whole tank should get it?

[Colu]

Looking at the meds you have used I would  treat for parasites with paracleanse or general cure  to cover all bases you could be dealing with a mycobacteria infection which are very difficult to treat it's difficult to no for sure have any of your fish go hollow bellys or passing white stringy faeces or showing flashing behaviour rubbing on things in the tank

Edited April 23, 2021 by Colu

[Plutoids Mom]

All of the fish have full bellies, and I haven't seen any white stringy poop.  The gold barb flashed a couple of times yesterday, but no one else is currently doing it that I've seen.  The rosy barb had done that in the past every once in a while.

[Colu]

It could be gill flukes I would treat the main tank with paracleanse

[Plutoids Mom]

My LFS was out of Paracleanse.  They suggested I try Furan-2 and Nox-Ich.  The gold barb has now died.  I gave the rosy barb the Nox-Ich since he is in the quarantine tank and has symptoms.  Going to try another LFS tomorrow for the Paracleanse.

Edited April 24, 2021 by Plutoids Mom

[Colu]

12 minutes ago, Plutoids Mom said:

My LFS was out of Paracleanse.  They suggested I try Furan-2 and Nox-Ich.  The gold barb has now died.  I gave the rosy barb the Nox-Ich since he is in the quarantine tank and has symptoms.  Going to try another LFS tomorrow for the Paracleanse.

I am no familiar with that med hopefully you can get paracleanse