Help, what do you suggest

[mseepman]

Today when I got up I noticed that my rabbit fish didn't comes out during feeding. I had noticed that he's grown thinner over the last few months despite eating okay. Today he appears to be done for. He barely swims and gets pulled into the power heads regularly. I've saved him three times from my Vortec. He's not interested in eating either and is struggling to breath.

All other fish are fine. I've done a 10% water change just to ensure water quality.

He was a good sized fish when I got him 6 years ago...is this just his time? I haven't ever had any disease in tank and all fish are years in this tank.

When should I remove him? I don't want him dying behind my rocks and unreacheable. I've never lost a large fish before...how does everyone dispose of them? Is there a humane way to handle this?