So sorry for the loss of your gourami...So, bad news
My beloved Dwarf gouramie passed away a week or two ago, very suddenly. The morning he was fine and eating, la
Ter in the day he was very unresponsive and just floating beneith the survace, but head up.
So I placed him into my quarantine tank, just to be sure and give him a fighting chance.
Later that day he was laying at bottom of the tank, breathing very heavily. I put some medication in at that point to try to save him, but the next morning, he had passed away.
Now, my placo keeps bullying my Corydoras paleatus. Evertime he payed down at the bottom, he would be chased away. He was starting tog et a little lethargic, so I tried to rehoke him with my Buenos Aires tetra in the ~120 little tank, went very well for a few days, lethargy seemingly improved, but this morning, I found him stuck to the filter... He is still alive, but has some sores on the side that was stuck, so now I set up the quarantine tank again, and am currently getting him acclimated to the water, but it's not looking good for him.
I've never had a live fish stuck to the filter, some dead ones rarely, but I have no idea how to help him.
I have medication for a large variety of desease, should I add that once he is aclimated?
And sorry your other fish not doing well... Are you able to share a picture of the sick fish? You don't want to use medications. A lot of the medications for fish can be really harsh and cause issues, with only a handful of medicines that actually do good.