Colour Spreading?

[blinky000]

A couple of months ago, I got my Pluto and he had a very definitive red/white border on his anal fin (please forgive the tatty fins, he's a reformed tail biter):

And here he was about a week ago. You can see that the red has spread down through the white of his fin:

I've never seen colour changes like this in bettas, apart from marbles. Is there any reason it would have just started spreading now or is it purely down to genetics?

 

[supermonkey]

I'm no expert, but I would assume this a dyed fish and the colour is still spreading?

 

[fuzzynicki]

I'm no expert, but I would assume this a dyed fish and the colour is still spreading?

Bettas come in all varieties of colours! They are not dyed It is common for them to change colour like the boy in the photo. I bought a male who at 5 months old looked completely white apart from a few small greeny spots. Now he is a proper blue butterfly,- with only a bit of white on his fins! It's just one of the things I love about them!