Scribbled losing white band why?

[Chicago]

I have a male and female scribbled. They are doing great for several months now. Eat anything and the male is very friendly. Will hand feed and actually nippy my hands when in the tank. I noticed over the past month or so. The white behind the gills and eye is shrinking. This is occurring in the female also. Any thoughts as to why. Again. Both are doing great. They are not stressed. And are eating great. Thanks

 

[Chicago]

No one.

 

[ginpang]

I'm guessing you already looked into this ... But when we Google for pictures of this beautiful fish , the juveniles always have a very wide bar . And some pictured specimen have a very little patch or no white at all.
Would it fair to think that it's just a Color transition in relation to size and maturity ?!
I'm just throwing it out there...any one?

 

[Chicago]

that's is what I am wondering.. the female has no lines or spots left. body is almost solid blue black with the yellow.. white is almost gone.. the male still has the nice lines as males do.. but no longer has very little white left.