What next ... tail sinking
Excellent sticky ...
We had four discuss with plague ... thought it was white spot and 2 died before I saw this thread ... treated as you said ... one more died but one has survived...
We put him back in the main tank (which has only has an albino rainbow shark in it and a black tetra)
Discus has been eating a little but nor regularly. ph is 6.4.
Now he seems to be swimming at a 15 degree nose up angle. He seems to "sink" and then works his way up again.
Any ideas on what is going on?