Bruise??

[Coolibabes]

Got home last night and discovered this bruise/blemish on the underside of my Vlamingii tang. The fish is not displaying any discomfort whatsoever and still eats like a pig!

Can anyone confirm what it is and possibly what caused it? Maybe had a run in with a stinging coral, e.g. anemone??

Is it something I should be worried about?

See pic below

 

[Gwynhidwy]

It looks like a sting from an anemone or possibly a coral. I would keep an eye on it, but expect it to resolve on its own.