Hi all, I've been watching this question "Why not use an aquarium for a cage?" surface regularly here and elsewhere and feel I must speak up. There is one very good reason not to house anything in an aquarium without a ventilation system. Animals breath air and when they do, they remove oxygen and replace it with carbondioxide. Carbondioxide is heavier than air and will fill low or enclosed areas without ventilation. Even fish require a ventilator when living in an aquarium. Granted, if there is a moving animal in the aquarium, the air will get stirred up, but it still will be less oxygenated than an open area, especially when that animal is at rest (i.e. sleeping - which ferrets do a lot of). It won't kill the animals, but imagine living at the top of Pikes Peak, a nice place to visit but, you can't catch your breath when you're up there and you feel like s**t when you come down. An animals body needs oxygen to work properly and depriving it of it because "you have a perfectly good aquarium and just can't let it go to waste" is just ..... well, o.k.... Stupid! Now go out and find, make or buy a proper home for your furry (or scaled) friends! And while your at it buy them lots of neat toys and treats and ..... uh oh. Looks like another case of ferret hypnotism! Anyway I guess I'm done being sanctimonious now. Have a great fuzzie day, CHERYL [Posted in FML issue 1760]