Ever since I moved Shiny into his divided 10 gallon, he has started marbling.
He is a pastel pink betta with a black beard that always sticks out slightly behind his gills. Right after I bought him he developed two tiny black dots on his anal fin, but he hasn't changed until I moved him to the filtered, divided 10 gal. Now he's getting some black coloring on each side, and I think even some slight blue metallic closer to his face. I know sometimes bettas can look like a totally different fish after they marble, but how long does that take? I'm wondering if my fish will continue to marble until he is really colorful, or if this is all the color he will get. Don't get me wrong- I like his color now. But it's also kind of fun that he could be changing colors.