Unexplainable colour change...any suggestions?

[Bellus Bellator]

Hi my boy Piggy over the last 3 weeks has been going through a strange colour loss through his dorsal fin that has now slowly spread onto the scales on his back.
At first I thought it was fin rot and treated him and then just to be safe treated him for a fungal infection too.No fins were damaged during this time.They seem thinner than they were before(but that's possibly because they are now a pinkish white/translucent) but no tears,no holes and they have continued to have new growth tips the whole time.
His appetite is normal,energy levels are normal,still wants to kill the thermometer :) Haven't caught him scratching or any other unexplainable behaviour.
I'm sorry that I haven't filled out the sticky because I forgot where it is but

water temp = 78f
Tank= 10g filtered natural plant
Ammonia= 0
nitrite= 0
nitrate=0
Food= 10 pellets twice daily(his name is piggy after all :D) 1 day fast once weekly.No live or frozen food is given as treat (need to get more)

He used to be such a lovely perfect steel blue crowntail....he's still lovely but now he's got his funny little pink dorsal fin......but I am very worried by the fact that it is spreading very slowly towards the tips of the fin(which are still blue) and down onto his body.

Has anyone seen this before? Does he have some sort of illness and can I treat it?
Thank you.

[asukabetta]

try posting a pic, it would help people help you, I heard betta's change color and such perhaps it's just that?

[deso]

If his fins are pink and are growing, and he's not lethargic or otherwise acting oddly, perhaps he's carrying the marble gene and is just going through a colour changing phase.

The only thing that stands out to me is that you're feeding him 20 pellets. Even if the pellets are really small, that sounds like far too much food to me. Most people on here with grown male bettas that aren't the giant breed feed 7 a day maximum.

[Bellus Bellator]

Oopps! Thanks for the advice Deso.They are very tiny pellets but I will lower the amount,he is a little fat I suppose.

I took pictures but the fin just looked a very pale blue and the true pinkish white didn't come up at all so I felt like it didn't really show the true contrast.

I guess I have to cross my fingers and hope that what I'm seeing is some sort of marbling now that he's becoming fully grown.

[deso]

Haha no problem. He may beg you for food when you cut down, but just be tough and say "no" ;) Three or four in the morning and three or four at night should be perfect for him, if he's a big guy and the pellets are small. As long as his new colour isn't a "rotting" grey or black, then I think he's just growing up.