A week ago Friday I got a male betta fish. I cycled the tank for 24 hours, but I didn't test it for water temp or ammonia or nitrate levels. A week later, my betta fish seems healthy. He swims around and he eats his food like a good little boy and he doesn't seem lethargic or anything. He even started his bubble nest the day after I put him in his tank. The only problem is his coloring.
When I got him, he was completely blue except for one strand of red fin. Now, the tips of his fins are the right color and from a distance he looks fine, but when you get up close you see that his body has paled considerably. More red has appeared mixed with the blue, and the blue looks like it's tinged with purple. The top of his head is devoid of color completely.
Is this normal, or is it a real problem? Is it a water temperature issue, or a disease?