Angel color change?

[Chief Tom]

This morning I noticed what appeared to be a gash in my angelfishs head! I thought he got into a fight but it's a completely peaceful tank so I figured he smashed into a rock or something. Anyway I looked at it with a magnifying glass and it appears to be a new color spot. Theres also some red coming through his veils. Poor fish has been in 3different tanks and watched his wife get murdered when some fool(me) thought it would be ok to temporarily keep a flowerhorn with them. I'm actually surprised he's still alive much less being tank boss. Viva ?!

 

[Yuki-Rihwa]

I'm not an expert nor fish science researcher but I saw this happened few times in my fish keeping life, also happened on Goldfish too. A black color fish turn 100% golden/yellowish color in a few months times and color changed stay for the rest of its life.

 

[Chief Tom]

Just scared me. At first glance it looks like a bloody gash.

 

[FJB]

Very cool that you wwere able to document that.
I don't know of angel coloration changes, which almost certainly would not be the same in wild versus domesticated strains. But goldfish and koi (and possibly other fish) change colors in a snap, with reds and black blotching coming and going, or at various stages of development. I didnt know angels can do that.
Very nice fish!