We have had interesting experiences with ferrets and
aquariums.  The ferrets seem oblivious to the fish, but
love the charcoal bags in the filters we use.  We use
the basket type filter and unless we tape down the
lids, the ferrets open the top and pull out the charcoal
bags and proceed to spread the charcoal everywhere
they can manage.  On the lighter side, we had a beautiful
set of black ferret foot prints marching across a
futon cover once thanks to this.
 
        Mike, Erica, Ian, Inigo, Buttercup, ...
 
[Posted in FML issue 0606]