Hi I bought him many months ago. He is in a bowl about the size of a large dinner plate, I don't think he's cramped. He's a black Betta fish with dark blue fins. Less than a week ago, I noticed the top of his head (forehead) has a smallish silver patch. He seems kinda lazy but he has his times where he swims around and has fun. What could be causing this? What is it? Do I just need to change his water more often or something? Could it be because it's a little colder outside (I live in southern Florida, so it's not like it's snowing).