I have a male betta, Bluebeard, and he acts fine. He's a bit shy but not so much that he won't come up to greet me when I come near the tank. He swims around a lot and eats whenever I feed him. However, I noticed that on his top fin, just above his body, there are some blue spots. His coloring is a purplish blue with a bit of red in some places. Are these just freckles or a sign of a disease?
Without a picture, it's hard to tell for sure but I'd say it's just regular coloring, like freckles as you said. Usually when anything goes wrong on a betta, like parasites or fungus, the color is white, gray, black, or red, but not blue. Especially if the blue is the same color as the rest of him. He could also be changing color as he matures, if he was very young when you first got him.