Red Patch On Betta

So, i’m honestly not sure if there is something wrong with my betta or not. He has this red patch on his fin. When I got him, he was all white. That was maybe two months ago. He has since slowly changed colors, transitioning to dark blue with a black face. But he has a red patch on his fin. It isn’t raised or bumpy. It really looks like it is scale color. It looks so out of place though. Is this some sort of disease, or am I overreacting?

 

You mean that small bit of red on his ventral fin?

 

Yes. Not sure if I am being silly, but i've spent a lot of time staring at it and figured I might as well get some other opinions.

 

It looks very out of place, but looks just like natural colouring.

 

That’s what I thought. Thanks!