my betta.. who ive only had for a few weeks is completley blue... thats not the problem its just that his head and half his body has turned solid black!!! it looks really nice and i hope he turns completley black.. but i wanna mek sure that this black is natural.. and not some horrible disease... any thoughts?

bettas do tend to change color - plus they look WAY different at home than they do in their little cups in the florescent lighting in the stores. just to check...how's your params?