Violet Goby - Caved in head?

[Redliw]

Howdy!
I have a violet goby that's head seems to have caved in. He's been a bit sluggish since I bought him (Wal-Mart about 1 week ago) but I figgered they were a sort of sluggish fish that liked to hide anyway and I've actually tried to scoop him out several times thinking he had died. I tried to scoop him toward the front of the tank for a pic but he is extremely uncooperative. All other fish seem fine, water's good. His head just really looks wrinkled and is sunk in. Should I put him in a seperate tank? I've never seen anything like this before. Any suggestions on what I could do for him?
Thank you!!

 

[Redliw]

My cam won't zoom in clearly so it's not the best...

He has tiny little eyes anyway but they and his head in general are so sunk in they aren't visable. I don't know how he's even alive.

 

[guppy]

This looks like either an injury or a serious infection, possibly of fish tuberculosis, isolate the fish and make sure you raise the salt to at least 1-2tbsp/5 gallons, I really don't think the odds are good.

 

[Redliw]

Yup, poor feller died sometime between 3 and 7 this morning.
So, I scooped him out, did a partial water change (anything dead in the tank creeps me out) and replaced the salt (for the few gallons I removed).
I checked him out when I got him out of the tank, and it honestly just looked like the poor guy shriveled up but no sign of injury (to my newbie eye).
I have awful luck with fish from Wal-Mart, they have all died and occassionally given everything else in my tank ich before going belly up. Lessons learned, eh?
Anyway, thanks for the input.