I have two blood parrots that are around 4''-5" and there in a 30 gallon tank with a trimca that is smaller than them and the parrots turn pale on some days then turn red on other days. The smaller one( male) is usually a reddish color but turns pale sometimes, while the bigger one ( female) is almost always a light pink.I was wondering if this is normal because when I first bought them from the pet store they were a bright red color but started to turn pale a few months after I bought them. What could have caused them to turn pale?