Mollie Changing Colour?

[fishy55599]

I have a male silver mollie that is getting a organge colour, it didnt have this colouration wen i brought it.
Could it be because my 3 female mollies are rubbing up beside him trying to breed?
Could it be because he sees them and changes colour to be the same as them?
Any other possibilitys?
Anybody have any idea why this is?

 

[OldMan47]

If he is developing an orange colored stripe along the top edge of his dorsal fin, he is merely maturing.

 

[fishy55599]

It is a stripe on his top fin and tail