80F is Ok. There is some agent bacteria or otherwise that is causing the problem.
I am told by my LFS which is the best in town that 30-40% water change every three days is ok. I highly recommend water changes 30% every three days. Be asue wnatever itis, it is in the water. Until you figure out what itis. the water change is yourlife line. 30% minimum every three days. I consider your situation as emergency as you may loose them all. So 30% water chang every three days is very appropriate.
Good luck,
If you have another tank, you may wish to remove the fish without symptoms.
I am told by my LFS which is the best in town that 30-40% water change every three days is ok. I highly recommend water changes 30% every three days. Be asue wnatever itis, it is in the water. Until you figure out what itis. the water change is yourlife line. 30% minimum every three days. I consider your situation as emergency as you may loose them all. So 30% water chang every three days is very appropriate.
Good luck,
If you have another tank, you may wish to remove the fish without symptoms.