I have a little black moor. He had ich, aka white spot disease, I put the recommended amount of salt in his tank, 3 tsp per gallon (he’s in a 5gal quarantine tank) and let the temp bump up to about 27-28degrees. For a couple days the spots were going, he was looking happier and he perked up. This was about a two weeks ago. A couple days ago I noticed he looked a little inactive. His water wasn’t very good. I did changes and got it back down to perfect. I have kept doing that most days for the past 5 or 6 days , but he’s not looking any better. He is just staying at the top of the tank and not moving (pic below). He looks really sick. Is there anything I can do for him? If not, I don’t want him to suffer so what it be more humane to euthanise him? Pls advice really appreciated. I really want him to live, but I don’t want him to suffer [emoji17].