try cleaning your glass and getting a side shot while you take the pic at an angle. there is a lot of glare and water depositis. the only reason i say this is because my betta's silvery scales appeared seemingly overnight (like a day or two) not too long after i got him. he colored up nicely given a nice new environment and good foods. How long have you had him?
i dont want you to be necessarily alarmed if that is the case with your betta. from that angle, it's hard to tell. are the spots raised? like grains of salt? maybe Ich if so, but to me, something says the picture quality gives those viewing it false observations due to the glare and water spots.
if he's eating and acting normal. no flicking or rubbing, id say its just his scales coloring up and he's got some silvery ones like mine.
good luck and cheers.
