What is this fish sick with?

[Khai]

I was walking through a LFS when I noticed a halfblack angel fish lying on the ground. He looked normal on one side and then completely sick on the other. I took a photo of him...

Please note, this is not my fish, not in my tank etc.

 

[kkdoughboy]

I hope it's not your photo either cause I can't see shot!

 

[kkdoughboy]

Joke on me I can see the photo now.

 

[kkdoughboy]

Umm what does the healthy side look like? Fish almost looks lime he's PH burned. Photo!?

 

[Khai]

It was strange, on the other side he looked like a decently healthy half black.

 

[Khai]

He had something on/in his eye also...

 

[Gwynhidwy]

The spot on his eye looks like a fluke, the reddining around his gills looks like ammonia burn to me. Could just be damage from flukes though.