My parrots are laying on the bottom of the tank. One is even laying on its side. My husband read that sometimes if they are constipated they will do this. They have always been very active and now they only come up to get feed or when I talk to them. Are they dying? My husband put a new fish in the tank, a fish that eats the slime off the tank. Could this fish have brought a disease into the tank? We have had these four parrot's for over four years. Really don't want them to die.