Fish lost, 99% sure dead

[ickmagnet]

I haven't been able to spot my yellow tang anywhere today and looked everywhere in the tank. He's not a jumper but I searched the perimeter as well. He vanished. I noticed yesterday he was looking a bit sickly so I'm assuming he died and hid in a crevice or something.

My questions is, do I find him and remove him or just let nature take its course? I have a 180g tank with about 200 lb of live rock. It would take up a day moving my rocks all around and re-arranging trying to find the guy. I would obviously do a water change in a few days if I left him.

I have a pretty light bio-load (1 medium size hippo tank, 1 medium green wrasse, 1 smaller naso, 1 maroon clown, a large clam, and a medium rbta). I'm running a protein skimmer as well.