I bought 2 discus(2 inch each) suddenly from galiff last sunday. I had no plan for it. I had experience on discus keeping from year 2012-2015 and left 3 years back.
Now, I kept them in a poorly maintained planted aquarium and one of them caught Discus plague on the next day i bought.
Symptoms are following:
Leaning to one side
being shy, hiding behind aquarium filters with clamped fins.
Turning dark
sometimes heavy breathing
Excessive mucus and slime coat production.
Scratching and rubbing against aquarium objects
fin rot
White patches fish's skin
Cloudy water due to large amount of slime coat and protein.
New Arrangement:
Shifted both to a 2 feet X 1 feet X 1.5 feet aquarium (half water filled) and water change 70-80% daily
Medicine:
doxycycline one capsule 100mg per day (tetracycline not available at market).
Food:
Not sure what was their food habit.
Tried tetra bits but not eating. eating only earth worm

Filter:
No filter for now, only air bubble. I have canister filter but not added to this aquarium at this condition.
No heater.
Please suggest any medicine or what i need to change in immediate effect.