Fungus Or Bacteria?

[mnm123]

I saw my platy with these white marks on its body, not sure if its fungus or some kind of bacteria infection. 
 
 Can you please suggest me what it is.
 
P.S i am a noob

 

[AmtotheBurr]

When you look closely at it, does it appear that the scales are missing right there? Or is there a whiteish haze over the top of the scales?

 

[mnm123]

Looks like the scales are missing there.

 

[HarpyFishLover]

That looks like my guppy's tail. I shall follow this thread...