Help With A Down Mellon

[Cevoe]

This discus is approximately 4" to 5" and is in a 55 gallon tank with seven other discus, all 4" to 5" too, and six blue rams.
All eat and and all are healthy except for this particular fish.
He stopped eating a few days ago and he is also now showing a small amount of fin rot and is breathing a little heavier than usual.
Outside of these things, and a thinning down of his body, he swims and basically acts normal.
The typical food offered is light pellet and flake, some frozen mysis shrimp and a good feeding of frozen blood worms once a day.
This fish never ate anything but the blood worms and now is only going as far as taking it in and the spitting it out.
The water parmeters are zero amonia or nitrite and the ph is 6.0.
The temperature is 84 to 86 degrees.
The tank also has a large piece of driftwood (which I believe buffers the ph down so low) two small plants and a pebble-sized substrate.
Overhang filters move 600 gph and the water is changed 50% once weekly.
Any ideas on what this discus may have, how to treat or any other tips concerning the tank and houskeeping?
I will appreciate any advice.
Thanks,
Chris

[Cevoe]

I did not see the normal posts until after I submitted my question.
I read the thread that stated the sunken sides of a discus is usually due to nematodes or flagellates and the recommendation to use flubendazole, levimasole or piperazine.
Which in particular?
I also will be moving this fish to quarantine in a 40 gallon tank.
Thanks again.

[phat nguyen]

Hello Chris,
Sorry to hear about the condition of your sick fish.
It is better to treat the sick in a tank that hold about ten gallons of water.This way you don't have to spend too much money on Medicine and it is easier to change the water for each treatment.
Be sure to have a separate tools for the QT tank. You don't want to share the disease through out your other tanks. Hope to hear the good news from you soon.

Best wishes,
Perry Nguyen

[Cevoe]

Thanks, Perry.
I should be getting things underway today.
Chris