Julie
Mine also whistle, especially if they have been swimming around alot and are exausted and need to get air very quickly. It just sounds as if there isn’t enought room for the amount of air being pushed through because they needed air quickly. But, it can also be a sign of respiratory infection. Look for signs of lethargia, secretions from the mouth and nose and lack of apetite. Julie Tougas Chun-Ming Chew wrote: