Shiny silver gills

[Kelly5978]

Can anyone tell me what the shiny silver patch is on these 2 fishes gills? The smallest black one did NOT have it the last time I saw her, so it's NOT coloring. Thanks!
http://youtu.be/Vsk4KMbcUEQ

 

[f1shg33kz]

I didn't see anything wrong with them. The silver is very common on marble Angels.

 

[Kelly5978]

Okay. Hoping you are right. But, the little one seemed to develop one over night, and the Mohawk one's seemed to get smaller. Thx. They're not mine, but my friend will feel much better!