My blue betta gets pale around the face and gils almost daily. It doesn't last, and he's acting normally and eating, but I'm worried. I'm thinking it's because his 2-gallon bowl is getting too cold but I'm not sure. I've bought 2 heaters and for some reason both of them don't work or they only keep it at 72 degrees, it never gets any warmer. The ones I bought were 25 wat, which I would think would be plenty. Does this paleness mean he's sick or that he's just getting too cold? Thanks for any thoughts!