My betta's fins used to be really dark blue with hints of red and purple on his fins then a few weeks ago, he got a white ring around his head and it started to spread and it got wider. It's not fuzzy and it doesn't look like anything is on his scales. It looks like the color is being sucked out of his scales and fins. Now, as you can see in the picture, a lot of his fins are white. I've done partial water changes and I keep the water at a constant 82F. He's in a 5 gallon tank and he's about 2 years old. Before the color change, he used to make bubble nests and be really active, now he just kind of sits nears the surface or inside his house. He still eats normally though. Is he just getting old or is this a disease?