I have a blue, red, and white betta. I just got a new apartment an hour away from here so haven't been home as often to check up on him every single night. My brother has been feeding him every morning and night. He has a heater.
Lately, the past few days that I have checked on him, I've noticed that his body looks slightly green over the blue. He's also been very sluggish and likes to sit at the bottom of the tank. He's normally a very active fish.