Is this a big fluke or just a displaced fish scale?

[merkmerk73]

It has a sheen like a fish scale that I can see as it swims by

 

[Goaway]

#fishmedic

 

[Dburr1014]

@Jay Hemdal

 

[C4ctus99]

White light pictures will help when the fish medics get here

 

[C4ctus99]

Also this thread tells you what info they may need so they have it all ready when they see this

Some Helpful Hints When Posting or Responding to Threads in the Fish Disease Treatment and Diagnosis Section

Aquarium Fish Disease Problem Solving Determining the best course of action for a problem with your aquarium can be a difficult task. Even advanced aquarists will often need to seek the help of others for complicated or unique issues. Our intent here on Reef 2 Reef is to offer expert advice...

www.reef2reef.com

 

[Sharkbait19]

It looks like the results of an injury to me. Keep an eye on it. Better pics can confirm.