Today's update after first 25% water change yesterday (and adding back 25% of salt); he shows no improvement and his condition has worsened further. He lays on the bottom on his side and only moves to swim up for air before floating back down to the bottom. No reaction to me moving my hands around the tub to get his attention, not even in fear or skittishness. Unfortunately I don't think he'll bounce back from this. If he does pass, I'm hoping if I describe his symptoms here maybe his condition could be figured out. I don't mean to sound like I'm replacing him already, but I just want to make sure my tank will be safe for any fish in the future. Still staying hopeful though, I'm not giving up on him.