Since I got my betta (about September of 2012) he has changed colors. When I bought him at petsmart he was a very pale whitish color, and after the course of 1 to 2 months he gradually changed into a red and blue color. Recently though, I noticed the area below his dorsal fin turning a pale whitish color again. It's been about a week and half of his abdomen is that pale color now, it's almost like he's changing colors again. Is this normal? He's in a filtered and heated 5 gallon that has been cycled. There is no ammonia, nitrites, or nitrates in his water. I realize that bettas in the store are very stressed and will lose color and gain it back when under the proper conditions, but it shouldn't happen again?