There’s a white spot on my bettas head! What could it be?
It would be helpful if you could post a picture and say a bit about his living conditions- tank size, whether it's heated and filtered, the current water parameters for Ammonia, Nitrite, and Nitrate, when the last time you did a partial water change, and when you noticed the spot. It could be something as simple as him bumping his head and losing a scale. It could be more serious. Without pictures and more information it's hard to tell.