What is this flaky dry scale on my silver?

[Thee See 5]

My 15" silver has this single dry flaky looking scale on his body. It is not scratching it or anything. Anybody know what it is? Water params are good amm 0, nitrite 0, nitrate <5. Fish is swimming fine and is eating well. In a 240g if it matters.
Pic is kinda blurry but its the best I can do.

 

[shacklock]

if it isn't scratching then should not be much of a problem. try observing are there any worms or parasite growing around it.