long story short-i have a pretty overpopulated discus-community tank.
yesterday i got myself 2 new adult discus,both the most dominant the store had.
yesterday they were a rather stressed,as expected.
today towards lunch time one of them began laying sideways.....by late evening and as of now he's flaoting as if he's dead....his eyes are all white,slimecoat rather gone,color very pale,fins ripped....i would have said the poor thing is dead,but he's really trying to swim here and there and breathing a bit....

my water parameters are:
PH7.3
KH 6DKH
NH4 0
NO2 0
temprature 29c

tank is 250 liters. planted,heavily populated with a wide mix of tetras,a few gouramis and a whole bunch of catfish (a few L numbers and corys).
4 discus in total,all adults, and 4 angelfish,also adults.


can stress kill an adult,dominant discus within 24 hours!? ive been told it could be something called "new discus disease"? should i isolate the fish? any meds? HELP PLEASE i really dont want to lose the gorgeous,expansive guy....