Fading is weird, I have had some fade almost over night and others have taken months and others have never finished. But it is very cool to watch and spot the little changes.
From what I have witnessed with these faders don't trust what you see at first!...
I think the first part of the process seems to be quick because it's easier to see the lighter areas growing when the fish is mostly black. Once they are +50% faded it is harder to see any difference day to day. Mine has been in this state for roughly 3 months and might be 75% done, but he is a big fish at a year old. The smaller the fish is when it fades should shorten the timespan it takes to complete. The black scales on mine seem to melt away to a light grey and then to whatever base color its going to be.
Enjoy the ride, I am amazed by it every morning while having my coffee