Fading betta colors, is he sick?

Question
Hi there! I recently purchased my dear freind and soon after introducing him into his new home, his colors are beggining to fade. I have heard dull or pale tanks can cause this but his tank is colorful. The ph balance seems normal, 7.0 amonia level, and 0% chlorine. His water was a tiny bit acidic when he was introduced, but that was quickly taken care of. It does not have a filter being so small. His tank is fairly small, 1 1/2 gallon, But Foxy Shazam is a tiny red crowned fin betta. His tank is more than large enough for him, or atleast I think so? Plenty of room for fast swimming side to side, and up and down in the tank. He seems to be eating fine, recognizes me and enjoys the company. He seems happy. I really do hope you can help me figure out if somthing is wrong with the water or if he is sick.

Answer
Caleb,
The absolute minimum size tank for any male Betta is 2.5 gallons, but a 5 gallon is best. When testing the water, you also have to test for nitrites. This is what the ammonia turns into. He is also a tropical fish, and needs his water to be 80 degrees at all times. With a tank that small, it will be very hard, if at all, to get a heater to work properly. Once he gets in the right size tank, with a heater, you should see a big difference in him. He is fading because his water is not warm enough.