Need help to ID what's wrong with YT

[Oropher]

Yellow Tang seems normal, eating, swimming and occasionally neck to neck with Purple Tang. Only noticing something protunding on her right belly recently.
What's wrong with her?

 

[dwest]

@Jay Hemdal might be able to help

 

[Jay Hemdal Verified Community Expert]

The picture isn't quite clear enough to see, but I wonder if the purple tang tagged it?

Jay

 

[Oropher]

The picture isn't quite clear enough to see, but I wonder if the purple tang tagged it?

Jay

My YT is the dominant Tang over PT.

 

[Oropher]

My YT is the dominant Tang over PT.

I hope this video could help describing the problem.

Could be from the fighting also... Normally just torn fins.

 

[Oropher]

@Jay Hemdal : could it be ulcer?