Betta fishes will start losing their color when they are stressed over something. Check what had changed in his surrounding environment recently. Maybe it's an introduction of another aquatic animal, or a change in water temperature or salinity. This will lead to poor health if the color doesn't return.
You need to have you betta in atlest 5 gallons of water and check to make sure his fins and scales look the same. Make sure you are changing the water once a week because if it isn't clean he could be sick.
so i just cleaned his tank again, he is now puffed up swimming all around it, and into the walls? is he okay, im worried, i bought him for my son, and my son is very attached to him, how long is a bettas lifespan?
sorry i meant he had a 1 gallon tank, he is the only one living in it, when i bought him he was in a 3 gallon and i was told being the only fish in it, he would use to much energy checking for "intruders" in his tank.