Dear X: Fluid backup in or around the lungs in ferrets is most commonly the result of heart failure and the heart's inability to keep up with the blood coming to it. It has to go somewhere, like when a toilet backs up. In animals, it most commonly shows up in the abdomen, but around the lungs or in the lungs is also a common place. While it could conceivably occur with too much fluid - that is very uncommon - the kidneys are quite adept in moving it out of the body. You would either also have to have severely failing kidneys, or damage to the vessels in the lungs on top of the over-administration of fluids. And I think the fluids would probably have to be given IV - I have never heard of a ferret drowning from injudicious use of SQ fluids.... With kindest regards, Bruce Williams, DVM [Posted in FML issue 3680]